You want High Speed? Go back to 1935.

[oltmannd]

QUOTE: Originally posted by futuremodal

The point made in Peterson's topic headline should not be lost in all this. In 1935 railroads were on the verge of evolving into a higher speed transportation option, with higher speeds than 1935 highways and high enough speeds to compete with propeller driven aircraft over short to medium corridors. Since that time, highways speeds have increased, airline speeds have increased (although in the last few years increased terminal delays have probably doubled the amount of time a person needs to take out of his day to get from Point A to Point B, an important thing to note for those medium range corridors!), but the railroads top speeds have declined outside the NEC.

Perhaps the point to ponder is this: Did the railroads drop the ball while they had the lead in the race to reduce overall transit time in deference to the idea of increasing load factor at a cost of transit speed?

I don't think they dropped the ball at all. After WWII, they invested tons of money into the track and equipment to lure passengers. ACL tried to get most of their RR up to 100 mph for 24 hr running from NY to Miami. PRR and NYC actually tried some sub-16 hour schedules for the Broadway and 20th Century.

But, none of it was enough. The auto and airlines just crushed the RRs and by the early 50s, it was obvious the game was over.

You might make the case that the RRs blundered by all those investments streamliners - money better spent on CTC or other improvements.

[Anonymous]

The railroads let everything go in the 50's when they stopped providing the passenger services to every little town of any value in the USA.

I suppose they could not be blamed as they lost the mail contracts, aircraft was getting dominant, autos were very convient way to get around and trucking was born from the war years.

I thought about running amtrack from Little rock to washington however the cost of a soutwest direct flight was much faster, cheaper and less of a hassle than spending 24 hours on a train that had to go to Chicago to make it to D.C.

I believe that someday we will have regional corridors that will link the nation together and it might be possible to make the same trip in a afternoon from Little Rock to D.C. But not in my life time.

[Anonymous]

The point made in Peterson's topic headline should not be lost in all this. In 1935 railroads were on the verge of evolving into a higher speed transportation option, with higher speeds than 1935 highways and high enough speeds to compete with propeller driven aircraft over short to medium corridors. Since that time, highways speeds have increased, airline speeds have increased (although in the last few years increased terminal delays have probably doubled the amount of time a person needs to take out of his day to get from Point A to Point B, an important thing to note for those medium range corridors!), but the railroads top speeds have declined outside the NEC.

Perhaps the point to ponder is this: Did the railroads drop the ball while they had the lead in the race to reduce overall transit time in deference to the idea of increasing load factor at a cost of transit speed?

[Overmod]

Part of the reason low-speed-acceleration improvement is so important in quarter-mile Top Fuel is because it's so difficult to translate engine power to traction in that range, while the overall time is so short.

If you look at the overall time savings resulting from even very high acceleration, consider the limiting case of 'immediate' acceleration, with the speed over the distance previously required for acceleration being assumed to be full 'cruise'. (The corresponding deceleration doesn't count for purposes of this discussion for a variety of reasons!) If even something as pathetically slow-accelerating as an AEM7 with a long train takes, say, 4 minutes to reach 120 mph, your best conceivable trip time would be reduced... a fraction of 4 minutes (I leave the precise mathematical solution of how much the reduction is to the reader... ;-})

The little increments add up on things like commuter runs... and yes, you need a higher absolute top speed to recover those minutes in proportion to higher cruise speed. But consider the design compromises usually necessary to produce high acceleration in a high-speed train (which needs to develop maximum horsepower at top speed, a very different thing from acceleration from a start, as you 389 Tri-Power GTO folks probably already know!)

Point is, you don't need to leave your motive power behind to save tare weight, and you don't need to cross a finish line a couple of hundredths before your competition to keep from being eliminated. Acceleration means considerably less, in absolute terms, outside contexts like those...

Might also remember that climbing grades at constant speed also requires a formal acceleration... watch your accelerator-travel increase, or calculate the rpm/torque factor for up and downshifts needed to maintain the constant speed and you'll see. The question then translates into whether your motive power can generate sufficient acceleration (or force divided by mass) to hold speed on a given upgrade profile...

Now, highiron's point about holding speed is significant, but in a sense is more important for direct-drive diesel trucks than for diesel-electrics. Something like 70% of a diesel's power is involved in performing the compression -- you get that back during a subsequent expansion, but it doesn't matter if the engine isn't performing useful work (e.g. idling) or if it needs to accelerate itself. That's one reason why diesels lose speed almost immediately when you reduce fueling, but don't recover it nearly as easily even when the engine has very large nominal torque rating. A transmission which keeps engine rpm in the powerband -- and an engine controller that keeps revs in the right part of the powerband even while the clutch is disengaged during a shift -- will produce much better running as well as significant gains in overall fuel efficiency. In a truck.

Diesel-electrics can optimize engine acceleration and speed against delivered kw (remember that about 3/4 of a kw is a hp) -- I believe modern DPU systems can do this considerably more optimally than the older 'run' systems which have to avoid very wide ranges which potentially contain resonances, and aren't optimized for best fuel burn.

Now, what you want is a hybrid locomotive with enough energy storage to allow fast loading of the traction motor system while the engine is coming up to speed in the relative absence of load, then being loaded down via modulated excitation of the main generator. THAT will satisfy Ed Blysard even more than the six-motor MK unit he mentioned...

[Anonymous]

QUOTE: Originally posted by Junctionfan

In France, I saw a SNCF electric locomotive going quite fast with a consist of single stacked containers; how fast do they go?

BTW-I have never been to France; I saw this in a video.

70 mph, give or take 5

[Anonymous]

Up829 I recall from my trucking days that acceleration costs time and money.

In the early 90's I was handed a Cummins 350 Big Cam 4 equippted truck and told to go from PA to Ohio. I spend much time working the gears trying to keep the truck at the speed limit on all of these little grades.

6 years ago I traveled the same road which included the 7 Mountains in a Detroit 460 backed by a Auto shift. The torque rating was pretty similar at 1350 pounds feet but the horse power between 350 and 460 was significant.

I did not "work" the gears anywhere near as much with the newer truck. Nor did I have to spend time accelerating back to posted speed limits on the grades. I cut something like 1 1/2 hours off that run.

I support power that backs speed rather than acceleration. Being able to climb 7 mountains in the newer truck at about 38 mph instead of 22 in the older truck made alot of difference.

Acceleration is costly, but being able to put power on the rail to maintain speed or climb grades fast is much more useful.

[Junctionfan]

In France, I saw a SNCF electric locomotive going quite fast with a consist of single stacked containers; how fast do they go?

BTW-I have never been to France; I saw this in a video.

[Anonymous]

I wasn't thinking of catapulting a train out of a station like an F14 off an aircraft carrier, but rather as a way to increase average speed without increasing top speed. I assume LIMs can be set up for any desired acceleration or speed and the only parts required on the train are fixed magnets.

Someone mentioned NHRA drag-racing and I understand some top-fuel drivers are beginning to experience problems with internal eye damage. It's also well known in drag racing that improved low speed acceleration has the most effect on elapsed time.

By advanced rail structure, I''ve been thinking along the lines of a pre-cast concrete structure similar to the hollow bridge sections used for highways. These would have 4-6 lanes on top for cars and trucks, double track for passenger trains inside the hollow section, and conduits for high voltage electic transmission lines as well. All but the roadway would be in a trench and could transition to a bridge structure as needed. Expensive, but it addresses 3 needs at once and should last a long time.

[Overmod]

Adding a bit to the LIM discussion: I'll bet you were looking at one of the modern roller-coaster designs when you asked the question...

As Don indicates, trains can't really use acceleration much over a few mph/sec ... anything that would 'throw' a standing passenger without handholds. In addition, you want a relatively smooth start, and no intermediate 'jerk' (high rate of change in the rate of acceleration). In order to use a reaction-rail LIM, you'd need a considerable amount of rail, plus all the magnetic structure needed to implement the motor structure on each and every locomotive or other vehicle expected to produce power. I don't see any particular application where this would be more cost-effective than motored axles (roller coasters not requiring motor action past the relatively short 'shoves' given by the LIM sections, and benefiting from low tare/low cost of having no powered axles...)

Where LIMs have been a 'preferred' railroad design solution is at the opposite end of the speed range, where rail/wheel traction begins to lie down and die for physical reasons at around 310 to 320mph, and you have increasing difficulty in establishing and maintaining external power supply even at very high voltage. By placing the powered motor structure on the right-of-way, and using the 'reaction rail' component on the vehicle(s), you can neatly overcome both considerations ... and get nifty high-speed braking capability (within the heat absorption and Curie limitations for the vehicle-mounted components). Above about 160mph or so, you can space out the individual coil driving sections and still get smooth enough impulse to maintain speed and provide incremental acceleration (for grade climbing, etc.) -- and 'wire' the coils so that relaxing induced magnetic field in one coil acts to help load up the 'next' coil in proper phase, which utilizes much of the power that would otherwise be wasted in motor action. (This is like an intermediate approach between straight rail and maglev).

With some care, this approach allows the use of low unsprung mass in suspension, even when comparatively heavy carbody mass is involved; it also decouples the forces involved in high-speed propulsion and braking from the suspension kinetics. But it is NOT a particularly good way to guarantee rocket-shot acceleration from stops, or to facilitate shorter timings between relatively closely-spaced stations, to the extent that would justify the very substantial capital and maintenance costs required for LIM design and implementation...

[oltmannd]

QUOTE: Originally posted by up829

Could linear induction motors built into advanced rail systems be used to assist HSR trains up to speed out of stations? Or is the horsepower required for top speed already capable of acceleration beyond what passengers can comfortably tolerate?

Passenger comfort limits acceleration to about 0.1g (~3 mph/sec). In transit applications, acceleration is critical. In LD pass train operation, it means much less.

[oltmannd]

QUOTE: Originally posted by jchnhtfd

I also bow to the experts. As usual, though, I have to say something (can't keep my mouth shut, can I?!).

And the something is this: what is your cost/benefit ratio? What can you charge? What is the best way -- across ALL modes of transportation -- to accomplish a specific task?

For example. What is the cost involved in making faster freight service possible, vs. the cost involved in making reliably scheduled freight service possible, and what is the customer willing to pay for either one? In many many situations (the auto parts industry is a splendid example) the criterion is that a specific car with a specific load of widgets arrives within a very narrow (often on the order of an hour) time window at a specific location -- this does not mean that it got there faster or slower, but that it got there on time. Similarly, for a blocked stack train from, say, the Port of Long Beach to Chicago, it is much more important that it arrive in Chicago at a specific time than that it got there at a specific speed.

In this connexion I would note that certain railroads have done remarkably well at instituting reliably scheduled freight service (and that the same railroads seem to have remarkably good operating ratios -- I wonder if there is a connexion there?) with relatively inexpensive (millions, not billions) investment in infrastructure, but significant cultural changes in train handling.

With regard to passenger service, again, what is the best way to handle a specific service demand, in terms of cost/benefit? (and keep in mind here that I am a really big Amtrak booster!). In some markets, it may be high speed rail. In some markets it may simply be more service with reliable schedules. In some markets it may be airline service (although the current security restrictions are changing the game there in radical and somewhat unpredictable ways) -- and in airline service, you have variables of the hub/spoke model vs. the point to point model. In some markets (horrors) it might even be buses...

jchnhtfd-

I like how you think...I'm not surprised to find you have an engineering background (except your spelling is too good!)

I would only add that once a shipper has established consistency, speed is important. If you can sqeeze a day or a shift of out of the transit time, you save inventory carrying cost for the customer - some of which you share with the customer thru increased rates based on increased value. Sometimes, knocking off a few hours in transit time will mean you cross a threshhold for the customer - perhaps having parts available for first shift instead of second.

Similarly, you might improve the cycle time of the equipment and reduce equipment costs - some of which you share with the customer thru reduced rates - perhaps as leverage or addition business with them elsewhere.

Knocking 5 minutes off 10000 shipments is NOT the same thing as knocking 1000 minutes off 50 shipment. It's how it fits into the whole business process that counts.

While it is critical to compare alternatives and their ROI's - just about every passenger rail study I've looked at compares several scenarios - , sometimes pure ROI isn't the final result. For example, you may compare an express bus plan with a commuter rail plan. The bus plan might have a greater ROI based on cost ot build and operate versus number of rides provided, but the commuter rail plan would carry several times the traffic. If the goal is to provide capacity, then the commuter rail plan would "win" since it helps avoid or delay some additional investment down the road.

[Anonymous]

QUOTE: Originally posted by up829

Could linear induction motors built into advanced rail systems be used to assist HSR trains up to speed out of stations? Or is the horsepower required for top speed already capable of acceleration beyond what passengers can comfortably tolerate?

It isnt the acceleration. Accelerations are pretty tame however I have ridden the London Underground and they use down grades to assist trains in getting up to speed and upgrades to slow down. (As well as flood control) and those speeds are pretty frisky.

If passengers can tolerate a 757 -500 leaving town at 140 mph from 0 down a runway they should be able to tolerate similar rates on a train. I have experienced acceleration that makes you lose your breath and hardly see. For the limits of Human Acceleration look at Top Fuel racing at over 320+ down a 1/4 mile. It is harder to move a human body much faster in the same time/distance without risking damage. And these are strapping strong drivers willing.. no.. lustful for the thrill of that power.

We have to accomodate all ages and medical conditions on trains so they cannot be thrown down the track ASAP by a lead footed hogger. (I am sorry for horribale choice of words but cannot think of rail terms) dont worry, they will be rolling along fast enough.

Once you are moving, then you gotta keep moving. That is why Europe and Japan has elevated trackage so that they dont have to play with cars, idiot kids and other stuff that interferes with safety and high speed.

Schedules once set they are very... dictating and unforgiving.

I recall one Steel Hauling contract explained to me that was worth approx 9 million dollars gross revenue annualy. The terms of the contract included a SPECIFIC departure and arrival time from shipper to receiver in the window of 10 hours exactly.

The first load ran out of hours while still 2 hours from customer. Investagation revealed the contract route was driven with a passenger car with 4 wheels in 10 hours while it normally took 12 for a trucker to cover it legally in a 20 hour period with a 8 hour break. Assuming one load per truck per day (24 hours)...

Hardly enough to feed factories making washing machines. You load several trucks per shift of 8 hours a day and expect them to arrive a day later round the clock. You need many trucks to do this work.

That leaves 4 hours to deal with any interruptions. That is pretty tight. One unscheduled inspection at a weight station can cost an hour alone.

You will need many trains to keep a decent level of service to the people. Twice a week service from Little Rock to wherever does not cut it. We want high speed availible hourly on the hour or close to it.

Recent HSR crash of a Japanese Train into a Apartment building revealed that the boy engineer was probably upset that he was behind schedule and also have "Blown" or "Overshot" a stations stop.

Japan prides itself on punctual trains that are almost timed to the second. It makes America look like a nation of tardy sleepy heads content to be leaving sometime in the morning.

Perhaps Japan's schedules are TOO tight, they need to loosen up just a tad bit.

We must be careful not to fall into the same trap.

[jchnhtfd]

I also bow to the experts. As usual, though, I have to say something (can't keep my mouth shut, can I?!).

And the something is this: what is your cost/benefit ratio? What can you charge? What is the best way -- across ALL modes of transportation -- to accomplish a specific task?

For example. What is the cost involved in making faster freight service possible, vs. the cost involved in making reliably scheduled freight service possible, and what is the customer willing to pay for either one? In many many situations (the auto parts industry is a splendid example) the criterion is that a specific car with a specific load of widgets arrives within a very narrow (often on the order of an hour) time window at a specific location -- this does not mean that it got there faster or slower, but that it got there on time. Similarly, for a blocked stack train from, say, the Port of Long Beach to Chicago, it is much more important that it arrive in Chicago at a specific time than that it got there at a specific speed.

In this connexion I would note that certain railroads have done remarkably well at instituting reliably scheduled freight service (and that the same railroads seem to have remarkably good operating ratios -- I wonder if there is a connexion there?) with relatively inexpensive (millions, not billions) investment in infrastructure, but significant cultural changes in train handling.

With regard to passenger service, again, what is the best way to handle a specific service demand, in terms of cost/benefit? (and keep in mind here that I am a really big Amtrak booster!). In some markets, it may be high speed rail. In some markets it may simply be more service with reliable schedules. In some markets it may be airline service (although the current security restrictions are changing the game there in radical and somewhat unpredictable ways) -- and in airline service, you have variables of the hub/spoke model vs. the point to point model. In some markets (horrors) it might even be buses...

[Anonymous]

Could linear induction motors built into advanced rail systems be used to assist HSR trains up to speed out of stations? Or is the horsepower required for top speed already capable of acceleration beyond what passengers can comfortably tolerate?

[Anonymous]

Ahem...

I have to humbly bow and scrap at the table of knowledge and beg pardon...

Truckers dont see 500 miles in 8 hours. 500 miles is a long day in some areas of the nation. One time I had a perfect DOT legal 500 mile run from NH to Md in 10 hours on I-95 traffic that was flawless that day. And this was in the days of 55 mph.

Out west many trains of double stacks race east out of the west coast and every one of those boxes would have been a long distance trucking haul just 12 years ago.

If you need to cover 500+_ miles in 8 hours you need a MPH Average of 62.5

Since most fleet trucks are "Casterated" by the companies who have self insured policies between 61-70 mph it is basically impossible to get 62.5 mph average.

I think that railroads will have to seriously beef up the speed and the variety of cargoes as well as offer MANY smaller intermodal yards CLOSER to the shippers and recievers to have any chance against the trucker.

I have decided that in the light of the deteroriating employment numbers that increases the shortage of drivers in the next ten years as people flee the harsh life of driving. They are told that they will make 45,000 first year. But after spending money in the truckstops etc... for food, showers and basically everything they do to get the job done on the road they might clear 10,000

In short, I see the death of Long Haul Trucking except in very specialized Produce, Customs Expedited, Air Cargo, FEd ex etc.. driven by teams who can roll 24/7

It is very difficult for a railroad to beat a Team truck. They can leave Baltimore midnight and be past Little Rock into Oklahoma by 24 hours.

Try getting a set of cargo trains out of Baltimore thru the choked rights of way, yards, slow orders and just plain too many rules causing alot of people to work on this one trip.

Until you can get high speed between Baltimore and Little Rock rail scenario versus a team truck and ship 200 cargo containers faster than that team truck then you might start to see things happening along HSR Freight.

Railroads are going to have to add equiptment, trackage and come up with innovative ways of stuffing more trains down the 500+ mile "Pipe" faster and with better costs to the customers who pay the lowest money to move the cargo.

[Anonymous]

Jack_S:

Regarding your incremental speed increase analysis, you are essentially correct, but you must remember that we are talking about constant movement over time, e.g. we're running that 500 corridor maybe 200 times or more per year, thus a measly 30 minute time savings between 100 mph and 110-ish mph, comes out to 100 hours or more of time savings per year. Time is money, so you must ask yourself what that 100 hours of time savings translates into in dollar terms. Again, the more time sensitive the commodity, the more money is saved per year with the 10 mph increase from 100 to 110 mph. So the key cost/benefit variable is: What is the highest sustainable speed and average trip speed needed for a train of 125 RoadRailers/RailRunners to beat the truckers in corridors of 500 miles or more? Again, the railroad will need a trip speed that compensates for the time needed to transfer between modes at each terminal. Since trucks can average between 50 and 60 mph dock to dock (an estimate, assumes 70+ mph on the highway) for an 8.5 hour 500 mile trip between the two terminals, if we are penalized 1 hour for modal transfer at each terminal, we need to average over 77 mph just to tie the truckers time at 6.5 hours plus 2 hours in terminal delays. Thus, to be safe (in terms of getting the shippers' business) we need to average at least 80 mph, and I would expect that in order to do that you'd need to be capable of sustained speeds of up to 120 mph.

CSSHEGEWISCH: Here's a poser - Which takes longer to stop? 1)Three 5,000 ton trains with two identical locomotives on each train, with the second and third trains following close enough to the first for the lead engineer to control all three via remote control, or 2)One 15,000 ton train with two lead locomotives, two DPU's one third of the way back, and two DPU's two thirds of the way back (e.g. all the locomotives are controlled by the lead engineer). Assume the train makeup between the locomotives is identical, and all have the same horsepower to ton ratio. Then turn the question around so that you are comparing one 5,000 ton train with the three 5,000 ton trains in terms of the stopping distance. Does the one 5,000 ton train stop quicker than the three closely following 5,000 ton trains? Wouldn't the engineer of the lead 5,000 ton train be able to stop the trailing two trains at the same rate as if he was only one 5,000 ton train?

The point is, it may depend on the distribution of the locomotives to determine if a 5,000 ton train stops quicker than a 15,000 ton train at the same relative rate of speed.

[Anonymous]

I am of the opinion that any HSR expansion in America would have to be well thought out, preferrably with a 20 or 30 year plan. For starters we should build HSR between metropolitan areas of 5 million. This would include a Philadelphia-Cleveland-Detroit-Chicago line, a Dallas-Houston line, a Tampa/St. Pete-Orlando-Miami line, a LA to San Francisco line, and a New York City-Toronto-Detroit-Chicago line. These would probably serve almost half of the nation's population with some sort of HSR.

Secondly, we should build HSR lines between metropolitan areas of 2 million, such as a Jacksonville to Orlando line, a New Orleans to Houston line, a St. Louis to Chicago line, a Minneapolis/St. Paul to Chicago line, a Cincinnati-Cleveland line, a Atlanta-Jacksonville line, a Atlanta to New Orleans line, and a Portland-Seattle-Vancouver line.

Eventually we should build HSR lines between as many metropolitan areas of 1 million or so, such as a Indianapolis-Louisville-Nashville-Atlanta line, a Atlanta-Charlotte-Greensboro-Raleigh-Richmond-DC line, a Monreal-New York City line, a St. Louis-Kansas City line, a Dallas-Kansas City or St. Louis line, a St. Louis-Memphis-New Orleans line, a Jacksonville-Raleigh line, a New Orleans to Jacksonville line, and possibly a Phoenix-LA line. With these lines we would be serving over 80 percent of American citizens.... and just about every state east of the Mississippi and over half of the states west of the Mississippi and east of the Rockies.

Its been my opinion that we do have enough density east of the Mississippi River, and in the direct states west of the Mississippi River, plus Texas and the eastern half of Oklahoma. We also have enough density south of San Francisco in California and north of Portland in the Pacific Northwest....

I will agree there isn't much density in the states west of those directly bordering the Mississippi River to the west coast....in the Rockies and on the Great Plains.... The only exception is the Denver area, and its a long ways from Kansas City.......

There would be two lines on the west coast, south of San Francisco and north of Portland. There would be a box east of the Rockies, Philly-Chicago-Dallas/Houston, Atlanta-DC.... Two lines to Chicago from the east coast, two lines to Florida from the northeast, DC-Atlanta-Jacksonville, DC-Jacksonville directly, and two lines thru the south, New Orleans-Atlanta, New Orleans-Jacksonville.... There would be a branch to Minneapolis, a branch to Montreal, a direct route from Chicago to Florida thru Atlanta, and a line thru Ohio....possibly connecting to Lousiville's line.....

One can offer more lines, but I am of the opinion these lines would be sufficient. Mileage estimate is less than 10,000 miles..... At a conservative rural estimate of $20 million a mile, we are looking at a $200 billion project..... $200 billion divided by 20 years is $10 billion a year.....

A one cent national sales tax on a $7 trillion GNP, is $70 billion a year..... Chicken feed.....really....... So its not really the costs that is keeping it from being built, its only a matter of will power.....choosing to do so.........Its also not a matter of new technology, the technology already exists and can be purchased off the shelf..... Plus a one cent sales tax won't break anyone's bank.........

[daveklepper]

My E-mail address is [e-mail], and I can download Acrobat and j__, whatever it is, if the data can fit on a floppy, not a CD.

The other aspect of my track structure is the possibility of elevated light rail, returning to the original Charles Harvey 1868 West Side Patent Elevated Railway on 9th Avenue and Greenwich St. in Manhattan, which had sort of Y or U with a beam underneath, supports, under two horizontal beams that were also the rails. No crossties. Propulsion was by cable. The one car was light. Crossties and more substantial construction came around six year later when steam power took over.

But with modern materials a two rail electrification should be possible without crossties and with near-conventional light rail cars that also run as streetcars or subway trains or interurban cars on conventional track structure, but then give all the advantages of monorail as an elevated without loss of flexibility.

That is really what they should be doing in Seattle instead of the monorail. They could then share the present bus tunnel with Sound Transit's light rail line and not build a parallel el structure.

But is clear that the historic crosstie construction should not be last and only word.

[Overmod]

Daveklepper, I think there are a couple of significant problems with your proposed track structure as described, but I also think they can be addressed. You don't have your e-mail posted, so e-mail me on this (I don't think the forum members by and large are too interested in advanced high-speed ROW design). My own version of this approach comes out of the German experiments with sprung track in the early 1920s, and some research in "permanent" track alignment by the concrete industry that I came across in the early '70s. You put the running geometry adjustment into a continuous dual concrete beam system -- I think a two-plane truss is needed for gauge and cross-level trim, and to keep the railheads from rotating out of alignment under various loads (etc.) -- then handle the civil alignment with a separate structure, like a glorified concrete trough with 'hard points', and adjustment between the two for fine leveling, surfacing, etc.

We figured something like this would be essential if service above ca. 185mph for sustained periods was ever going to be cost-effective to support in the United States. One thing that sprung track allows is the possibility of extremely high speed, as the energy that goes into the track is easily controlled without major geometry changes, stochastic shock forces, etc. Another thing is that you can make relatively fast, automatable, and stable adjustments to your alignment, without having to worry about the sort of crap that happened at Point of Rocks. A nontrivial advantage, too, is that there's much less problem with pieces of ballast and other crap flying up to whack your expensive high-speed undercarriage (and things near the line, too!) which becomes important as you get into elevated speed ranges.

Capitalization is, of course, quite substantial, which is why you won't find extensive discussion of this stuff in the usual places, but note that the ROW work can be done with modified continuous-paving equipment, and the beam components can be fabricated via modular processes similar to those used for structural precast concrete elements -- akin, too, to the methods for making concrete ties. Advantages of sprung track are very real for heavy, slow-speed freight operations, too (anywhere, in fact, there is significant deformation of any component of the track structure because of loading characteristics or "geo" problems with the roadbed or underlying ground profile.


Just to cover something about this rail load business: Speed and weight do different things to track. There is a very well defined range (which mudchicken, drephpe, etc. can give you exactly for different types of rail) under which loading gives relatively little plastic deformation, but above which cold flow becomes extreme. Your requirements for grinding, etc. become much greater when that range is exceeded, and this is a major factor (as I understand it) in the discussion over permitted wheel loadings. By contrast, a certain amount of wheel loading is required to establi***he 'work-hardened' martensitic layer on freshly-ground modern rail -- otherwise, it can start to 'go bad' in weird ways with surprising speed! (I remember that NJT had to do something unusual to harden some of the rail on its lines after grinding; normal commuter train loadings wouldn't do it)

Speed forces are more short-term shock related in the vertical plane and lateral axes; see the Hatfield reports for some of the factors involved. Note that the acceleration and braking forces, magnified as they are, show up as analogues of what is described above for pavement. (I'll also mention that LWR and CWR exhibit considerable creep in the 'down' direction on grades, especially when held in those elastic Pandrol-type clips, for quite similar dynamic reasons!)


A point about aerodynamic drag (with no criticism at all of Jack S implied) -- don't use scaling and analogies from typical aerospace industry work: they don't really apply in the right proportion. A train is similar to a very long, thin projectile, a bit like a javelin, in terms of its aerodynamics: the cube law proportion applies strictly only to frontal area -- which even on something with a Cd of 1 is very small in proportion to mass, momentum, etc.

You also get some pressure (and at higher speeds still, shock) shielding from the 'trapped' air that builds up in front of the train. This will produce nominal effective drag reduction at the speed ranges typical of high-speed rail -- go higher still and you get ghastly eddies and nonlinear flow effects in this 'virtual nose-cone', but not the boat-anchor effect that a strict application of cube law to physical reality would give.

The big effects in railroads have always been crosswind interactions and drag induced on intercar interruptions. Ask any railroader who's pulled automobile cars, or empty coal trains (the coal in full hoppers 'n gons provides rather effective streamlining but empty ones have huge vortices in the 'bins') or, for that matter, stack trains with tight vs. loose intercar spacing. Interestingly enough, one of futuremodal's patents (IIRC) in part addresses this situation even at normal stack-train speeds, by providing a (nominally cost-effective) way to shield the bluff ends of containers on adjacent cars with long spacing (as required by the trucks and draft gear between drop wells). Same effects apply to high-speed passenger trains (there were even accounts of this in Trains in the late '60s or early '70s) -- that's why the sides ought to be curved, and the gaps between cars shielded or provided with active means of generating stable flow turbulence at small energy cost which will allow smooth slipstream airflow over the gap areas.

Blah, blah, blah. Sorry, I find this stuff interesting even if few others of you do... ;-}


I like Don's incremental approach for implementation, although I suspect that most of the places where the ROW is available have too many curves to make non-active-tilt trains at true high-speed operation workable... and by contrast don't take advantage of the VHSR ability to run neatly up 8 to 10% grades (with proper spiral transition of VERTICAL curvature) with minimal overall power cost. I suspect that keeping superelevation comparatively low is an operational requirement for dual-purpose track, which again strongly argues in favor of tilting equipment for speeds much in excess of 100mph "cost-effectively" in the overall picture. I won't rehash any of the prior threads regarding mixed-speed operation (or extending one-speed operation into higher speed ranges) except to note that Don's proposal makes mixed operation more thinkable than most of the alternatives I've seen...

[Anonymous]

QUOTE: Originally posted by tree68
In defense of HI2003 - While the difference between 100 mph and 120 mph is indeed 20 mph, throwing in starts and stops and the additional time needed for each means the difference in average speeds for a given trip at each speed won't be 20 mph. I don't know where HI2003 got the 4 mph number, but it's probably not far off the mark for at least some runs. Of course, the number of stops, and the length of the sustained maximum speed makes a difference, too.

You are right on with that comment. Back in the 1930's when the Pennsy was still learning how to best use its new electrification they ran two identical passenger trains on the same schedule. They wanted to see how much time could be shaved off of the schedule by allowing the locomotives to run slightly faster. So on one train the locomotive was geared for 100 MPH while the other was geared for 90 MPH. Everyone was surprised when it turned out that the locomotive geared for 100 MPH required a longer, not a shorter schedule. The reason was acceleration. The 90 MPH train could get up to speed in a reasonable time. By the time the 100 MPH train reached speed it was nearly time to start slowing for the next station.

[jchnhtfd]

Let's see now...

First, on forces involved vs. speed: required guidance (lateral and vertical) forces increase with the square of the speed. That is, it takes four times as much force to achieve a certain guidance at 50 as it does at 25. So any change in track geometry from perfectly straight (yeah, right!) will take four times the force if you double the speed. Going from 70 to 100 mph just doubles the force. You have two choices: much better track geometry for high speed, or much higher forces. Since there is a very definite maximum force which can be exerted before either you climb a rail (not recommended) or break a rail (also not recommended), your track geometry has to be much better at even slightly higher speeds. Ask mudchicken!

On superelevation: for safety, the superelevation on a curve should never be set so great that a stopped train may topple off. In fact, it should never be so high that a train will stringline. This plus passenger comfort, more than anything else, limits the maximum speed for a given curvature. If you have the clearances for tilt trains, you can go considerably faster (there are specific formulae which give safe speed for a given degree of curvature and superelevation).

Braking: this is partly a braking ratio problem, as noted above. However, it is also an energy dissipation problem. The energy which must be dissipated in stopping increases with the square of the speed, not linearly: like force, to stop from 50 requires getting rid of 4 times as much energy as stopping from 25. This energy has to go somewhere, and in virtually all cases it goes as heat. There have been a number of studies on this. The bottom line is that the heat absorbed raises the temperature of the brakes. The temperature will rise to the point where the heat from braking can be re-radiated to the surroundings (heating the air or what have you). The problem is that above a certain temperature (varies with the brake materials) the brakes will 'fade', to use the automotive term, and you find, quite abruptly, that you have no brakes at all. There have been a number of runaways on mountain grades because of this. Thus it is suggested that heavy trains run slower, so that there is at least a fighting chance of getting them stopped before the brakes fade completely. There is a reason for speed limits...

Eastside's comments on the Milwaukee Atlantics and Hudsons fits with my sources... as far as I recall, the consistent high speed with steam record still rests with Nigel Gresley's magnificent Mallards.

From a safety standpoint, I am dismayed at the concept of multiple independent high speed vehicles (minivans) which Tomtrain suggested. I agree that on first glance, it looks attractive. However, to get the capacity of a rail system, you would have to have extremely close following distances among independent vehicles. This would require that the entire vehicle be fail operational -- that is, any failure (mechanical or electronic) would have to occur in such a way as to not impede the continuing operation of the vehicle. In applications such as NASCAR this is done by highly trained and superbly talented drivers, and even there bad things do happen now and then. I have some doubts as to whether it could be done -- economically -- on a large scale, however, particularly assuming that it is all done by automation.

Oh and yes -- Lancairs are a lot of fun to fly, but I liked my Arrow! For sheer speed and sex, though, the Tomcat the Navy let me play with for a while was kind of fun, too...

[Anonymous]

Moderate High Speeds are just fine for what I have in mind.
Getting people from small citys like Toledo OH to major airport hubs like Cleveland or Detroit. They park there car for free or a small fee at the train station then get on a train at 110 miles per hour 85 miles away to the airport.
They would be droped off IN the airport and clear customs and luggage enroute on the train.

[daveklepper]

Yeh, but where do those taxes on the ticket go? It stays in the airline business. That is the point. Also, a lot depends on where the runway is. Real estate taxes on the Grand Junction Airport's property would be pretty low fi the airport had not attracted some business, bu Kansas City's airport would have to pay tens or hundreds of millions. And again, there are the highways to bring people to the airport and back.

[jockellis]

G'day, Y'all,
American rail might be on the right track if you had Dr. Thomas Durant and the Big Four working their magic on Congress as they did in the 1860s. However, today it is the highway lobby which has the money to spend on Washington's elite while passenger rail is owned by that government and cannot shower its own leaders with campaign financing. We have that same problem down here in Georgia. Atlantans have among the worst commutes in the country and all our leaders (formerly Democratic and now Republican) can think of is ways of pouring more lanes of concrete.
High speed rail is nothing but a cop out which allows politicians an out for putting money where it really belongs, passenger service at normal speeds to normal places. They can say they are for high speed rail then let AMTRAK sink because it does not provide HSR. Later, they will say they have changed their minds on HSR because of the cost. So then they have made their masters at the highway construction industry happy and will continue to receive campaign contributions.
Jock Ellis
Cumming, GA US of A

[oltmannd]

QUOTE: Originally posted by CSSHEGEWISCH

Perhaps the experienced railroaders can help me out but it appears that FM is unaware of the different braking requirements for stopping 13,000 tons of coal from even 45 MPH compared to stopping a 5,000-ton intermodal from 70 MPH. Speed restrictions for mineral freight are there for a reason.

By comparison, restricting speed is defined as being able to stop short of an obstruction not to exceed 15 MPH, e.g. restricting speed is determined in part by the consist of the train and its stopping distance.

I think you are getting at the braking ration issue. Since the max braking force, by design, is geared to the empty car wt, as the load/tare ration increases, the braking distances when loaded increase.

Empty/load sensing braking (which these days would likely be part of some sort of ECP implementation) would "solve" this problem.

Anybody have $3-5,000 per car to spend for ECP? (and you don't get any return at all until all cars are equipped!) For an industry that stuggles to keep track in good repair and buy enough cars and locomotives to begin with, ECP is out of the question!

[oltmannd]

QUOTE: Originally posted by rr_guy

Trying to overlay a high-speed network on the existing infrastructure is going to be a tough sell. And buying right-of-way in today's environment runs into problems with the NIMBY crowd or suddenly discovering the most valuable real-estate on the planet ("You want to buy a 200 foot wide strip of my land? Hmmm.....").

I agree that trying to overlay a high speed network over the existing network would be tough and expensive. I was thinking more along the lines of starting by adding an addtional higher speed track (say class 5 or 6 as terrain, conditions permit) on existing ROW where no land aquisition or earthmoving would be required. e.g a third track from Albany to Buffalo or a second track from Raleigh to Charlotte. You'd integrate it into the existing line for meets, passing and maintenance, etc. At the very least, the additional capacity and flexibility would aid ftr RR operation reliability and may even help them develop some new market niches (e.g. team driver competitive intermodal, perhaps?)

[CSSHEGEWISCH]

Perhaps the experienced railroaders can help me out but it appears that FM is unaware of the different braking requirements for stopping 13,000 tons of coal from even 45 MPH compared to stopping a 5,000-ton intermodal from 70 MPH. Speed restrictions for mineral freight are there for a reason.

By comparison, restricting speed is defined as being able to stop short of an obstruction not to exceed 15 MPH, e.g. restricting speed is determined in part by the consist of the train and its stopping distance.

[Anonymous]

I think that the "Lost taxes" on that runway is more than recouped by a passenger tax of a few dollars a head levied on the airport and paid for by you and I.

I clean forgot about the areodynamics I had my head down heah on the rail too long.

Jack_S IMHO It is not the gain in time, but average miles an hour overall. One bad case of slowdown of a few minutes (15 minutes) can totally destroy that time savings.

It is difficult to get any organized political body such as Congress to do anything that will expedite High speed. I think that this is because our elected lawmakers are chauffered about in limos and charter jets insulated from the grubby "Masses" that has to go to work every morning.

It is my hope that Private Sector can make something happen for the USA in our life time.

[daveklepper]

Again, when you talk about building runways, you are forgetting the value of the LAND. Factor in the value of the land and real estate taxes that are lost by devoting it to airport runways, and possibly upgrading the track to high speed may just come out way ahead. Depends of course on which pair of cities and where the airport is located, etc, etc. And how do you propose to get the added people between their destinations and the airport? More highways, more LAND. The right of way of the train already exists and in most cases goes downtown where people usually want to go.