Maglev "North American railroads need heavier engineering than European designs" That is because our trains run into cars all the time! And most of that danger is from idiots, and apparently there are fewer of them in Britain.
"North American railroads need heavier engineering than European designs"
That is because our trains run into cars all the time! And most of that danger is from idiots, and apparently there are fewer of them in Britain.
Never too old to have a happy childhood!
European freight trains are also appreciably lighter than comparable North American equipment. A European freight train of 2500 tons is considered heavy.
With HEP, isn't there also the issue of how many HEP cars each HEP locomotive can supply? When VIA is running the peak season Canadian (or specials like its Veterans Train of three years back), there is a 8 cars per F40 limit, and a maximum train length of 24 cars and three F40s, due to HEP power requirements and the limits on how much pass-through current each car can carry.
I know the export equivalent of the F40 that EMD sold to Ireland's railways has had a dismal failure rate, mostly due to HEP problems, and those engines have been repeatedly derated, from seven to six to five HEP cars per engine.
Jim in Ottawa
Here are two a sample videos of LIRR with two locomotives on seemingly short six-car trains.
http://www.youtube.com/watch?v=-_QhDyFYW34
http://www.youtube.com/watch?v=u6ZX3IdzqPE
Oops, and did I say pantographs and LIRR? I meant to say "I am stupid." And I don't really think of "locomotive" to be exclusive of electric service.
jkeatonisn't there also the issue of how many HEP cars each HEP locomotive can supply?
Somebody said in the US an 18-car passenger train has always? had to get all its HEP from one unit, even if the train has two or three units. On rare occasions F40s have pulled 18-car trains-- to Seattle Seahawks games, if nowhere else-- so maybe 800 kW is enough. But HEP demand will depend on weather...
The only locomotives Amtrak had that "disobeyed" the one loco per HEP rule were the P30CH's. They had a pair of engine gen sets in each and could train line to other units. The trick is to bring the gen sets online in phase with the other already on line. Lots of icky electrical gear, particularly back in the "old days". If you bring the generator online out of phase - BANG!
I once saw a pair of P30s hauling an excursion of 19 Amfleet around the Horseshoe Curve.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Back to the years of the HEP changeover 75-80 roughly Amtrak used converted baggage cars with two Detroit V-12 71TT (Twin Turbos) rated at 750 HP Each if old memory serves me right they were rated at 550 KW each unit, two to a baggage car and were designed to phase both gensets to feed power to the train. We also had a few E-8-E-9 Locomotives equipped with the same HEP power packages. I was standing in New Haven, Ct. station when a broken down E-60 electric hauled by a hijacked Conrail SW-1500!!, arrived with an Amtrak train of 18 new Amfleet cars....temp outside was 5 degrees above zero...off came the dead power. Train was WAAAAY behind schedule...in backs two E-8 locos of which only the rear engine had operational HEP both of which were running with the power circuit breakers open. Coupled to train and hooked up HEP and the Electrician closed the breaker which showed only 300 KW's on the meters on the control panel. Both engine blew copious amounts of blue smoke until the combustion chambers warmed up under load (common). The electrician noted until the train started to depart the Kw's increasing as a single brakeman on the train started at the rear of the train and walked car to car turning on the hvac heating system on each car which is the overhead heater/AC units one to each end of each car. By the time the train was on the old NH Shoreline he reached the last car and turned on it's heating system. The turn on one car at a time was to avoid overloading the generators. Each Amfleet car could pull on power up a continuous 85 Kw's per car at maximum draw quickly overloading the HEP generator breakers.Once power was up and the cars systems turned on slowly as the systems powered up and reached operating temperatures the current demand dropped off.
I used to work train 60-61 The Montrealer Penn station to New Haven off the spare board and while checking the HEP car before departing Penn Station one night Noted an average of 225-2275 KW's power flow to the train combo amfleet/Heritage cars totaling 19 cars that night running on ONE generator...the other generator was shutdown but serviceable.
The MBTA in Boston used to use ex GM&O F-3 locomotives rebuilt as FP-10's with a Cummins 450 HP 6 cylinder engine hooked up to a 335 KW generator...back then it was SOP to turn the heating system on each car one at a time by one crew member to avoid triping out the HEP. Once all were on there was no problem unless the HEP failed.
Amtrak F-40PH's the first 30 units numbered 200-229 had 500 KW HEP installed which drew 700 HP off the prime mover leaving 2300 HP for traction to move the train..roughly the power of an E8. Later ones have as stated before 800 KW HEP units installed which use at max load 1100 HP off the prime mover. keep in mind this HEP load varies constantly. As an Engineer myself if I needed an extra 700-1100 HP to get over a mountain POOF!!! Off goes the HEP until I get to the top at which point a push of the button restores power to the train.
Another point where Amtrak over designs is the air compressor on each EMD engine. They use the optional 6 cylinder 400 CFM compressor, the standard is a 3 cylinder 254 CFM unit which is more than enough. The E units used a 2 cylinder 90 to125 CFM compressors on each engine. The 400 CFM unit was a lot of extra weight and Normal 0 MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} unnecessary capacity. Amtrak trains use a train lined main Normal 0 MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} reservoir air line but remember the HEP..turn it on and the prime mover winds up to 897 RPM and the air compressor is driven of the crankshaft
I ran across something years ago that referred to Amtrak performance standards for acceleration and braking. I remember an acceleration curve where a train would attain roughly 75 mph in a mile on the way to at least 125 mph for both diesel and electric. Because of the distance covered at faster speeds, ~95 mph was reached in 2 miles and ~110 mph in 3 miles. This is pretty quick and explains the seemingly extravagant use of power as a general practice, and the number of units at least previously "required" for a train. How arbitrary is such a standard; and what went into it?
More relevant, is this rate of acceleration justified for most regional "day train" services, or can a significant fuel savings be obtained? It's not just recovering speed after station stops, but after curve and zone reductions, and after meets.
By comparison, I think it was Paul M that calculated a P42 with six Horizon cars could attain 110 mph in 4-1/2 miles.
HarveyK400 I ran across something years ago that referred to Amtrak performance standards for acceleration and braking. I remember an acceleration curve where a train would attain roughly 75 mph in a mile on the way to at least 125 mph for both diesel and electric. Because of the distance covered at faster speeds, ~95 mph was reached in 2 miles and ~110 mph in 3 miles. This is pretty quick and explains the seemingly extravagant use of power as a general practice, and the number of units at least previously "required" for a train. How arbitrary is such a standard; and what went into it? More relevant, is this rate of acceleration justified for most regional "day train" services, or can a significant fuel savings be obtained? It's not just recovering speed after station stops, but after curve and zone reductions, and after meets. By comparison, I think it was Paul M that calculated a P42 with six Horizon cars could attain 110 mph in 4-1/2 miles.
Your comments about needed acceleration and attainable speed is a good question. It is a reason why I am not that rah rah in favor of many calls for high speed rail. Too often it is over kill when there are numerous stops in short distances. Commuter rail is certainy ruled out but that's where you hear the cry for speed most often.
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I think the only way to accurately assess HP requirements for train service is to do a series of simualtions over the route and compare running times. Then, plug the various running times into the ridership model for the route and equipment utilization and employee productivity models for the service and see what the overall effect is.
There is certainly a point of diminishing returns, but it is likely route specific.
One thing not talked about much is the speed which the locomotive loads. On a LD train, with stops every 40 miles or so, it doesn't matter much if the locomotive gets to full load in 20 seconds or 90 seconds, but for shorter hauls, it can be a factor. GE locomotives can take up to a full minute before they are even at 1/3 of max HP. EMDs are typically at full HP after 25 seconds or so.
That a locomotive can take 60 seconds and not even be close to full HP is something I had never accounted for in simulations I hade run. That GE units were that slow to load is something I was not aware.
Why I had originally asked the question is that in response to one of the proposals for LD service, I remember a friend in an advocacy group reacting to "only one locomotive on a train." I got to wondering whether Amtrak was putting more power on trains as an engineering factor-of-safety to compensate for their level of failures on locomotives, rather than in response to the type of simulations Don Oltmann is talking about.
Metra runs 11-car commuter trains with a single F40, but it seems an 11-car train on Amtrak runs with a pair of P42's. about double the tractive effort and 3 times the HP. Did Amtrak ever get any "unit reduction" with the higher HP P42's, say, a pair of P42's replacing 3 F40's in the Mountain West?
I am not talking about underpowering train or overloading locomotives, but when a "standard" corridor consist has a P42 and 4 Horizon cars, you are talking 1000 HP/car which is Japan Bullet Train level of HP (OK, the Bullet Train is MU so it doesn't have the weight of the locomotive and NPCC unit, but 4000 HP on a 4-car train is a lot of power).
If you have a pair of P42's on an LD train, from a HP perspective that is like a brace of 5-6 F units. Do they really need that much power since apart from AutoTrain Service, 12 cars is a common LD consist? Or is the second locomotive and "insurance policy." And if they need that much insurance against breakdown, what does that say about the locomotives or their maintenance procedures -- a Diesel-electric locomotive is mature tech by now.
If Amtrak needs a minimum 2 locomotives on an LD train, if they need a locomotive at one end and an NPCC on the other end for corridor trains, perhaps if they ever shop for new locomotives, they should look for something in the 2000-2500 HP range. Perhaps something like an 8-cyl GEVO, and perhaps something a lot lighter weight for reduced axle loading so it could be run faster on tilt trains without spreading the rails, which limits speed on the F59's used with the Cascades Talgo. I am thinking along the lines of the original LRC locomotive or the FM Speed Merchant as a lower-HP lower axle-loading unit.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
I was aware that the Metra F40CH-2 was programmed to load slowly until the train speed increased to where tractive effort no longer exceeded the adhesion limit. This was to prevent damage from wheel slip and keep a constant engine speed for hotel power. I was told the loading took 30 seconds.
The constant-speed engine would not work with a slip/adhesion control.
The calculations Paul M made for a 410-ton, 4,300-hp train resulted in a speed of 58 mph after a minute and tractive effort of ~27,000 lbs. The train attained 17 mph after 12 seconds before maximum tractive effort fell below the adhesion limit of 72,000 lbs. Taking a minute to load up would reduce tractive effort and acceleration appreciably, resulting in a much lower speed and distance after a minute. The lower speed would allow more than 27,000 lbs starting TE.
Someone may ask why not load up faster? On level track, 15 seconds may be possible; but even flat-land railroads have slight grades and the occassional hill. Being the standard system power that can be assigned to mountain-crossing trains, a much lower load-up is a practical compromise.
I very much agree that a light weight locomotive is needed for fast passenger train service. Mechanically the LRC was the equivalent of the MLW C-638, yet weighed under 240,000 lbs, similar to the EMD F-series. One source quoted only 210,000 lbs.
Notwithstanding crumple zones and safety cages, I'd prefer to see a raised cab like the Turbo Train, early City of Denver, Danish and Japanese regional trains.
The loading rate is governed by how fast the diesel engine handle increasing fuel rates. A four cycle with a free wheeling turbo has terrible turbo lag. You have to very gradually increase the fuel to allow the turbo to keep ever so slightly ahead of the load without smoking.
The two cycle EMD isn't as slow because it's turbo gets a boost from the gear drive - actually, the exhaust energy at the lower notches isn't sufficient to provide enough scavenging air for the engine. It HAS to have a gear driven blower. Still, it's about 20-25 seconds to full load from idle.
I have heard that nuclear power plants using Alco engines to run emergency cooling pumps can get up to full load in about 15 seconds. They used stored compressed air to spool the turbo up.
The practical limit on acceleration on a passenger train is 0.1G. For locomotive hauled trains this is rarely a problem since the locomotive's adhesion won't allow acceleration that great with more than a couple cars at any speed or horsepower.
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