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.
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 los
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.
I have Micro SD cards with 1 TB capacity.
The origin of this is in the 1920 Esch Act, which is the same place the 79mph/59mph speed conventions come from. Think of it as a quid pro quo for the release of Federal Control…
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 2
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…
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.
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.
The thing to have watched was the anticipated use of the lightweight equipment and diesel locomotives in the immediate postwar period, up to the date of the ICC Order itself. The trains could reach remarkable peak speeds on track that could still be frequently lined and surfaced by regular gangs (e.g. for steam service) – I remember reading about one railroad that was said to operate up to 127mph on a single-track line with semaphores. A great deal of potential high speed would be prevented simply by requiring inductor ATS equipment, let alone continuous cab signaling or other methods we’d deem desirable or necessary today.
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
Moore’s Law: https://en.wikipedia.org/wiki/Moore’s_law
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.
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.
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.
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.
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?