I read on a Trains Facebook posting that in cab signal technology has been required for class 1 railroads since 1922. If that's the case, why are there so many trackside signals? The article went on to state that due to PTC the old in cab signal technology would be removed, and that lineside signals will also become a thing of the past. I guess I don't understand how they all fit together..
Cab signals or another system imposing penalty applications when more restrictive indications are not acknowledged - such as ATS or ATC such as Santa Fe and C&NW had - were required when maximum speed was in excess of 79mph. PRR had extensive cab signal territory and UP likewise from Council Bluffs to Ogden. Sometime in the 90s, I believe, Conrail went to cab signal only operation in lieu of wayside signals on portions of the railroad west of Pittsburgh. With the advent of PTC NS has eliminated wayside signals in some regions and relies exclusively upon in-cab displays other than at control points. There may be other examples of this development on other roads. So the wayside signal has become superfluous where PTC exists, except where certain carriers elect to maintain a duplicate system. But where certain roads could not justify the expense of installing a cab signal system and needn't operate at speeds in excess of 79mph, wayside signals were necessary for operation above 49mph. Others may have more updated detail on current signaling changes.
Ulrich I read on a Trains Facebook posting that in cab signal technology has been required for class 1 railroads since 1922.
I read on a Trains Facebook posting that in cab signal technology has been required for class 1 railroads since 1922.
The ICC had a pilot program requiring that the class 1's equip at least one division with some sort of automatic train control or cab signalling. This was intended to be the beginning of equpping all of the major main lines with better protection. In reality, not much came out of this ICC order until the 40's when the ICC ordered that trains operating in non-ATC or cab signalled equipped track could not run at 80 MPH or faster.
The removal of wayside signals is in reference to the future goal of "rolling blocks" in PTC. It removes fixed blocks where occupancy is detected by track circuits. Instead, a train's location will be determined by GPS and trains communicating between themselves and a central computer complex. The rolling block invisions block length between trains to be determined by the computers, using data as to speed, train weight, location, etc to determine how far apart trains need to be to avoid running into the train ahead. That distance can change, hence the term rolling block.
Techies who are all for automating and computerizing everything are all for it. Even though the computing power may not (yet) be available. Some say they can eliminate track circuits and that railroad signal departments that are against it are just trying to save their positions and jobs.
It's true that with cab signals, wayside signals can be dispensed with except at junctions (siding switches, cross overs, etc.) and the approaches to them. CNW removed most of their waysides once they finished installing ATC almost 100 years ago. Some locations had signal reinstalled where trains from branch lines needed to use a portion of the ATC equipped main. There nonequipped engines could still lead trains over those portions. UP eventually installed waysides over most, if not all, of the exCNW.
Even though there were not wayside signals, with the noted exceptions, there were still fixed blocks. You get to know where the boundaries are (were) but I've now forgotten so many. When they installed the waysides they also changed most of the fixed block lengths.
Gone are the days when we would approach a relay box at a boundary at track speed and wonder if we were going to get train control and have to go to suppression and reduce speed to under 17 mph. Of course, ATC and CCS on the UP is gone. My area lost it last June and I think the rest of the system has seen it discontinued. That Facebook descriotion sounds a lot like what UP had on their employees' site.
Jeff
jeffhergertEven though the computing power may not (yet) be available.
Remember that Apollo 11 went to the moon with computers less sophisticated/powerful than your smart watch. And I think it's been said that computing power doubles on a regular basis - over a fairly short time.
I installed a hard drive in my Tandy 1000SX (years ago). It was fantastic - no more booting up from 5.25" floppies. The drive was a whopping 40 Mb. I have microSD chips now that are 128 Gb...
I suspect the obstacle will be the hardware - which has to cover thousands of miles of track.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
tree68... I installed a hard drive in my Tandy 1000SX (years ago). It was fantastic - no more booting up from 5.25" floppies. The drive was a whopping 40 Mb. I have microSD chips now that are 128 Gb... I suspect the obstacle will be the hardware - which has to cover thousands of miles of track.
I have Micro SD cards with 1 TB capacity.
Never too old to have a happy childhood!
Erik_MagThe ICC had a pilot program requiring that the class 1's equip at least one division with some sort of automatic train control or cab signalling.
What the law required (in 1920) was that one division of each Class I have automatic train stop (or better) installed for PASSENGER service on one test division (of the railroad's choice) by 1922. Then a second division by 1924, a third by 1926, etc. until all the passenger service was protected. The stated idea was that this would gradually and easily establish coverage, while building up a stable and enthusiastic base of equipment supply and design.
Remember that this was still the Government maintaining its 'safety' purview -- there was no mention of replacing wayside signals, mandating continuous indication or in-cab signals, in fact anything related to increasing operational effectiveness. This was still very much a 'run a red signal and be forced to stop completely (penalty braking was the term used, and you had to stop completely and get down off the locomotive to reset it, by intent).
The contemporary history of this effort was surprisingly rich and effective (Frank Sprague built a very effective company around the idea) but it was de-emphasized by Government intent in 1928 -- they decided railroad investment in grade-crossing safety or removal was a far more significant use of railroad dollars...
After Naperville, in 1947, the old Esch Act provisions regarding the necessity of speed control at 80mph or over got dusted off, and re-applied starting in 1950. In my opinion this slammed the door on a great deal of 'streamlined train' investment, including much of what would have been the perceived value of the Ingalls Shipbuliding approach to a 2000hp passenger locomotive.
BaltACDI have Micro SD cards with 1 TB capacity.
So far I haven't needed that. The card in my GoPro will do eight hours, even though the battery is only good for two (without outside assistance).
As a side note, 20 minutes of video on a GoPro comes in around 3 Gigabytes...
I visited a "defense megacenter" some years ago and saw a 1TB RAID drive - it filled a seven foot high 19 inch cabinet. How things have changed...
tree68 BaltACD I have Micro SD cards with 1 TB capacity. So far I haven't needed that. The card in my GoPro will do eight hours, even though the battery is only good for two (without outside assistance). As a side note, 20 minutes of video on a GoPro comes in around 3 Gigabytes... I visited a "defense megacenter" some years ago and saw a 1TB RAID drive - it filled a seven foot high 19 inch cabinet. How things have changed...
BaltACD I have Micro SD cards with 1 TB capacity.
When I had my first contact with 'mini' computers in 1978 - our system had a 10MB Disk drive that was the size of a two drawer legal size filing cabinet and weighed about 350 pounds and would run 3 weeks to a month without having the 11 inch platter physically crash against the read/write head.
Overmod After Naperville, in 1947, the old Esch Act provisions regarding the necessity of speed control at 80mph or over got dusted off, and re-applied starting in 1950. In my opinion this slammed the door on a great deal of 'streamlined train' investment, including much of what would have been the perceived value of the Ingalls Shipbuliding approach to a 2000hp passenger locomotive.
One of my "what-ifs" would have been production runs of the Westinghouse "Blue Goose" GTEL as a passenger locomotive. The waste heat from the turbine exhaust could have generated an impressive amount of steam for steam heat and steam ejector A/C. There might have been enough steam left over to power small steam turbine generators on the cars...
I doubt that the requirements for cab signals or ATS at speeds in excess of 79 MPH made much of a dent in the development of high-speed trains. There wasn't a perceived need for high-speed trains on a fleet basis at the time and Super Constellations and DC-7's were starting to have their effect on passenger loadings even before the 707 and DC-8.
CSSHEGEWISCHI doubt that the requirements for cab signals or ATS at speeds in excess of 79 MPH made much of a dent in the development of high-speed trains.
Meanwhile, the ride quality of those high-speed trains would have been decidedly unpleasant; that might have been taken for granted by prewar train riders, but would have rapidly become second-rate as larger 'turnpike-ready' cars and the larger aircraft mentioned came into predominance. I look with sorrow at the high expectation NYC had for the Train X service... and how quickly it disappeared once tried.
And then for any particular long-distance service, there's still the need for multiple full trainsets, including motive power. You need multiple tracks to run anything else on a railroad with high-speed passenger service; in fact ATSF had what was in effect a four-track main line where there were many opportunities for slower traffic to 'get out of the way' when necessary. All that was billed to the passenger department when the airlines got their routes free and the automobiles got theirs subsidized by governments and then by military expedience.
Another example: the very curtailed life of the Pacific Rail Equipment pendulum cars, which were essentially predicated on speeds enough to make their operating principle desirable or needed. To this day their demonstrator articulated set seems modern!
tree68And I think it's been said that computing power doubles on a regular basis - over a fairly short time.
Moore's Law: https://en.wikipedia.org/wiki/Moore%27s_law
jeffhergertTechies who are all for automating and computerizing everything are all for it. Even though the computing power may not (yet) be available.
There's a bigger elephant, and one that is quantifiable in the real world: GPS resolution is insufficient for the type of detection you need. The margin of error is small enough that it isn't a problem when you're flying a plane and the level of inaccuracy still puts your location inside your aircraft or covering the closing distance before "TURN LEFT" when you're driving. Or putting a missile on a target (horseshoes and hand grenades as it were). It is not sufficient enough to constantly and accurately tell you a train is on Track 1 or Track 2.
ORNHOO tree68 And I think it's been said that computing power doubles on a regular basis - over a fairly short time. Moore's Law: https://en.wikipedia.org/wiki/Moore%27s_law
tree68 And I think it's been said that computing power doubles on a regular basis - over a fairly short time.
There you go! Thanks!
We're pretty much at the end of Moore's Law era as the cost of setting up a new process is getting into the 11 figures territory. To keep the progression an even larger expenditure would be needed in two years, along with starting to deal with weird quantum effects.
A similar story took place with diesel locomotives, where a horsepower race was taking place from ~1945 to 1966 when 3600 hp was available from a prime mover. There's not much of a market for prime movers in excess of 4400 hp in the US.
Erik_MagWe're pretty much at the end of Moore's Law era as the cost of setting up a new process is getting into the 11 figures territory. To keep the progression an even larger expenditure would be needed in two years, along with starting to deal with weird quantum effects. A similar story took place with diesel locomotives, where a horsepower race was taking place from ~1945 to 1966 when 3600 hp was available from a prime mover. There's not much of a market for prime movers in excess of 4400 hp in the US.
I am viewing the 4400hp more as a matter of the power that traction motors can effectively transfer to the rail. My understanding, that the 6000hp engines transferring their power through 6 traction motors were slippery and not effective.
My observation is that trying to put more than 750hp per traction motor is exceeding the rail/wheel interface. If some technology can improve that figure then more horsepower from the prime move can be used to support the additional power to the rail.
I am not an engineer - I only know what I have observed.
BaltACD My understanding, that the 6000hp engines transferring their power through 6 traction motors were slippery and not effective.
I've read that this was a problem with the GP40's. They may have been "fast 40's" but they tended to be slippery. I think wheel slip technology caught up with that.
tree68 BaltACD My understanding, that the 6000hp engines transferring their power through 6 traction motors were slippery and not effective. I've read that this was a problem with the GP40's. They may have been "fast 40's" but they tended to be slippery. I think wheel slip technology caught up with that.
GP40's at 3000hp were at the limit of the then current technology of putting 750hp per traction motor to the rail. SD40's took the same 3000hp prime mover electrical output and distributed it through six traction motor - 500hp per traction motor and could relatively pull the world.
AC traction improved the rail/wheel adhesion equation significantly above the DC ability, but not to the level necessary to really harness 1000hp per traction motor.
BaltACDGP40's at 3000hp were at the limit of the then current technology of putting 750hp per traction motor to the rail. SD40's took the same 3000hp prime mover electrical output and distributed it through six traction motor - 500hp per traction motor and could relatively pull the world. AC traction improved the rail/wheel adhesion equation significantly above the DC ability, but not to the level necessary to really harness 1000hp per traction motor.
Rio Grande Valley, CFI,CFII
PJS1 BaltACD GP40's at 3000hp were at the limit of the then current technology of putting 750hp per traction motor to the rail. SD40's took the same 3000hp prime mover electrical output and distributed it through six traction motor - 500hp per traction motor and could relatively pull the world. AC traction improved the rail/wheel adhesion equation significantly above the DC ability, but not to the level necessary to really harness 1000hp per traction motor. What is the best indicator of the capability of a diesel locomotive. Is it the horsepower of the diesel engine, which I believe is commonly referred to as the prime mover, or is it the output of the electric motors? When the engineer opens the throttle, is it telling the electric motors to ask for more electric energy from the diesel engine, or is it ramping up the diesel engine to deliver more juice to the motors?
BaltACD GP40's at 3000hp were at the limit of the then current technology of putting 750hp per traction motor to the rail. SD40's took the same 3000hp prime mover electrical output and distributed it through six traction motor - 500hp per traction motor and could relatively pull the world. AC traction improved the rail/wheel adhesion equation significantly above the DC ability, but not to the level necessary to really harness 1000hp per traction motor.
A diesel-electric engine is in reality - a electricly motivated entity that carries around its diesel powered electrical generator, rather than being tethered to an external source of electricty, either overhead wire and third rail.
When the Engineer commands 'more power' from the traction motors the prime mover is linked so that the additional electrical power is generated from the generator that the prime mover is turning. The electrical generator needs to be turned at higher RPM to create more electrical power for the traction motors to consume as they work harder - either turning faster or being asked to motivate a heavier load or a combination of both.
PJS1What is the best indicator of the capability of a diesel locomotive. Is it the horsepower of the diesel engine, which I believe is commonly referred to as the prime mover, or is it the output of the electric motors?
Above about 10-12mph the motors can accommodate the full rated traction horsepower, which of course is determined by the diesel engine. Tractive effort then drops as a rectangular hyperbola with speed, up to the point where...
...overspeeding the traction motors causes damage like 'winding swell' and its evil consequence 'birdsnesting'. So once again the motors become the limiting factor, but this time from high rotational speed. Meanwhile the back EMF has been building up, and this can reach a balancing point with generated voltage which determines achievable top speed even in conditions of low train load or resistance.
When the engineer opens the throttle, is it telling the electric motors to ask for more electric energy from the diesel engine, or is it ramping up the diesel engine to deliver more juice to the motors?
Now, the situation has to be translated for use with AC drive, as here. The motors are likely to be a version of squirrel-cage induction motors, which generate their own armature exciting current as they run, and this is done by inducing current in the aluminum bars in the armature/rotor. Note that shortening the bars reduces the magnetic field they can develop, so a narrower motor is going to run into any problems an AC motor encounters quicker. Note that the control system generating the rotating AC field in the stator "knows" how to coordinate maximum turning strength with motor position, so even at locked-rotor, the motor can produce high continuous torque, but there are still limits to how much current you can run through a given motor before its blowers run out of capacity.
PJS1 What is the best indicator of the capability of a diesel locomotive. Is it the horsepower of the diesel engine, which I believe is commonly referred to as the prime mover, or is it the output of the electric motors?
Starting tractive effort and minimum continuous speed determine how heavy a train it can move. Horsepower tells you how fast it can move that train. Minimum continuous speed isn't just about the motors being able to survive the full output of the engine and generator, the unit also has to be able to put all that power to the rail without slipping excessively.
The 6000 HP units can't start any heavier a train than the 4000 HP AC traction units of equal weight, but they can accelerate the same train to a higher speed.
Greetings from Alberta
-an Articulate Malcontent
SD70DudeThe 6000 HP units can't start any heavier a train than the 4000 HP AC traction units of equal weight, but they can accelerate the same train to a higher speed.
I read years ago that, given sufficient traction and appropriate gearing, one could move a pretty substantial train with a 5 HP lawn mower engine. Just not very fast...
tree68 SD70Dude The 6000 HP units can't start any heavier a train than the 4000 HP AC traction units of equal weight, but they can accelerate the same train to a higher speed. I read years ago that, given sufficient traction and appropriate gearing, one could move a pretty substantial train with a 5 HP lawn mower engine. Just not very fast...
SD70Dude The 6000 HP units can't start any heavier a train than the 4000 HP AC traction units of equal weight, but they can accelerate the same train to a higher speed.
Back when I was working in B&O's Clark Ave. Yard I watched the Valley Local with a SW-1 move 84 loads of cement out of the yard over what passed for a 'hump' at Clark Ave. and continue on to the customer at the timetable point known as Willow. They didn't move fast, but the 600hp SW-1 kept all 8000+ tons moving. Took well over a hour to make the 4 miles to Willow, but they made it.
One thing we tend to overlook is just how slow steam engines were ascending grades with maximum tonnage. 4 or 5 MPH was the norm.
BaltACD tree68 SD70Dude The 6000 HP units can't start any heavier a train than the 4000 HP AC traction units of equal weight, but they can accelerate the same train to a higher speed. I read years ago that, given sufficient traction and appropriate gearing, one could move a pretty substantial train with a 5 HP lawn mower engine. Just not very fast... Back when I was working in B&O's Clark Ave. Yard I watched the Valley Local with a SW-1 move 84 loads of cement out of the yard over what passed for a 'hump' at Clark Ave. and continue on to the customer at the timetable point known as Willow. They didn't move fast, but the 600hp SW-1 kept all 8000+ tons moving. Took well over a hour to make the 4 miles to Willow, but they made it. One thing we tend to overlook is just how slow steam engines were ascending grades with maximum tonnage. 4 or 5 MPH was the norm.
Yes, and what an experience that must have been.. these massive articulateds dragging loads of coal over Sandpatch..to be trackside to see that!
Ulrich BaltACD tree68 SD70Dude The 6000 HP units can't start any heavier a train than the 4000 HP AC traction units of equal weight, but they can accelerate the same train to a higher speed. I read years ago that, given sufficient traction and appropriate gearing, one could move a pretty substantial train with a 5 HP lawn mower engine. Just not very fast... Back when I was working in B&O's Clark Ave. Yard I watched the Valley Local with a SW-1 move 84 loads of cement out of the yard over what passed for a 'hump' at Clark Ave. and continue on to the customer at the timetable point known as Willow. They didn't move fast, but the 600hp SW-1 kept all 8000+ tons moving. Took well over a hour to make the 4 miles to Willow, but they made it. One thing we tend to overlook is just how slow steam engines were ascending grades with maximum tonnage. 4 or 5 MPH was the norm. Yes, and what an experience that must have been.. these massive articulateds dragging loads of coal over Sandpatch..to be trackside to see that!
As a kid I attended a B&O Pittsburgh Division picnic held at a picnic ground adjacent to the P&W Subdivision at Mars, PA which is on Bakerstown Hill between Allison Park, PA and Bakerstown, PA. This was in 1953 or 54 and a Westbound coal train was climbing the hill - A Mallet on the head end and two more Mallet's on the rear shoving - cinders rained down from the sky for about 10 minutes after the helpers cleared the area.
As a young adult, I worked the Operators position at Bakerstown. Westbound coal trains would be climbing the hill with 4 or 5 untits (F7's or GP9's) on the head end. You could hear their exhaust bark a minute or two ahead of the announceator bell when the wind was blowing from the South. When the engines would start by the office they would be right at their minimum continuous speed of approximately 11 MPH. About 30 cars TT West of the office the grade began its descent down the other side of the hill. The first 30 or so cars clicked past the office at the same cadence as the engines did - once the engine crested the grade and began the descent, the clicking cadence of the cars gradually picked up to the point when the caboose with a three unit helper shoving went past the office they were doing the allowed 30 MPH. Once the helper passed the office, the job required me to hand line the trailing point crossovers and signal the helper crew so they could reverse direction and proceed back down the hill back to Pittsburgh for their next shove. At the time the P&W Sub was double track with curent of traffic signaling - West on track 1, East on track 2.
Thanks for the insights. They are very helpful.
BaltACD As a young adult, I worked the Operators position at Bakerstown. Westbound coal trains would be climbing the hill with 4 or 5 untits (F7's or GP9's) on the head end. You could hear their exhaust bark a minute or two ahead of the announceator bell when the wind was blowing from the South. When the engines would start by the office they would be right at their minimum continuous speed of approximately 11 MPH.
As a young adult, I worked the Operators position at Bakerstown. Westbound coal trains would be climbing the hill with 4 or 5 untits (F7's or GP9's) on the head end. You could hear their exhaust bark a minute or two ahead of the announceator bell when the wind was blowing from the South. When the engines would start by the office they would be right at their minimum continuous speed of approximately 11 MPH.
When I was first learning about the various models of diesel locomotives, the distinction between an F3 and an F7 confused me as they both were 1500HP locomotives. I recently ran across an article in a ate 40's issue of Railway Mechanical Engineer that went into detail of the differences in electrical equipment between the F3 and F7. The gist was that for a given gear ratio, the F7 had a higher continuous tractive effort and thus a lower minimum continuous speed than the F3.
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