CN 0001 the latest thing in CN equipment. Distributed Braking Container for mid-train air brake use.
Winnipeg 2/01/2019 Taylor Woolston
You look like you’re wearing a tuxedo
What makes you think I’m not?
Kinda strange looking: Is it simply an large air tank supply(with some sort of control gear)? Is there an auxiliary diesel engine to provide tha air supply?
Years ago, the locomotive ‘control system’ used by Southern Rwy [ie: possibly Locotrol(?)] was mounted in a boxcar to provide an engineer control of a train’s DPU’s. Is this CN 001 something like that? Or just use a regular locomotive in DPU ? This looks, sort of like, a problem looking for a solution. [2c]
As I recall, they’ve been using specially equipped boxcars for the same purpose for years.
Is this for pumping up the brake pipe, now that we have such long trains?
Is it a diesel engine (not locomotive) with a compressor? And it’s radio-controlled?
I think these cars predate the current trend toward long trains - being due instead to the cold temperatures in the north country.
Much ‘closer to home’ the ‘other’ Canadian carrier (CP) is famous for ‘robot’ midtrain control cars.
The CN idea is to provide ‘easily loaded and connected’ additional recharge, presumably at much higher volume and greater long-term reliability than a little locomotive compressor, in what may be cold weather on critical grades. I presume it also includes DPU-like ability to vent the trainpipe to accelerate both service and emergency applications. (It would not need ‘radio’ to accomplish that; the ‘shockwave’ propagating down the trainline after an emergency application would trigger further volume release to start setting up individual cars outward from the ‘container’ within the time of propagation at the effective speed of sound in the trainline – I think quicker in cold weather.
In my opinion it’s good common sense to put this in a container, adequately insulated, sledded, and shockproofed, as a great deal of deployment flexibility is realized thereby (instead of using a boxcar or old baggage car or B-unit arrangement). Nothing more complicated than a single spine underframe or single well would be needed to run it like one of the CP robots anyway. If more than one is needed in a consist … dray it in if needed and have the intermodal loading equipment drop it in for carmen (riding the dray if necessary) to connect up in a few minutes. Presumably deadhead or transfer moves (for example traffic asymmetry) can be easily handled by dropping the container on the next available space on an intermodal consist – even easier if the thing is within weight and balance to be doublestacked, as I suspect it would be.
I susp
place that unit 2/3rds back in the train then the front locos and it can each pump up 1/3 of a train. That function has become a good charastic of DPU consists. DPU On back of train has front and rear each charge up about half of a train, That is what shoud have been done on the CP runaway among other items.
But it wouldn’t work that way. The ‘midtrain’ unit would be pumping into both ‘thirds’ of the train adjacent to it equally, with the pressure becoming asymmetrical as ‘contribution’ from the two locomotives on the front eventually starts reaching the middle third of the train consist.
Situation is a bit different if you were to prevent the DPU from pumping into the trainline ‘ahead’, so it only does 1/3 of the recharge while the other 2/3 is handled (effectively 1/3 apiece in air mass-flow terms) by the head end power. But a moment’s reflection will begin to show problems in practice – big, illegal, irrational sorts of problems, if you were to ask me – with setting up Westinghouse one-pipe accelerated-release brakes to let you do that.
To accomplish what you want would be to put two DPUs at the 2/3 point in the consist, with only a single engine on the point. That should give you the rough ‘one-third apiece’ effect, but you would start getting some interesting effects with node runout and runin that wouldn’t occur to the same extent with power biased toward the front. Some of the folks with real-world Locotrol experience can comment on how well this would work for train handling.
I think it is less about the capability of the compresser and more of a function of total train line which is the limitation.
As information, the Great Northern used 40’ box cars (about 6 or 7) as air repeater cars for their winter operations. I worked in the BN’s Northtown Diesel Material from 1981 to about 1985 and saw approximately 6 50’ plug door (former BN) box cars also fitted with a diesel engine and air pump. Northtown Diesel was the shop chosen to maintain all the cars. About July or August, a pipefitter (who dealt with air pumps) would order two or three cars to Northtown Caboose Track 2 for checking and winterizing the cars. After he was done with those cars, Diesel Control would order each car to Grand Forks, Havre, or other terminal for the winter operation of those cars. In the spring, the cars returned to Northtown for summer storage.
Ed Burns from Northtown Yard.
[quote user=“Overmod”]
samfp1943
Years ago, the locomotive ‘control system’ used by Southern Rwy [ie: possibly Locotrol(?)] was mounted in a boxcar to provide an engineer control of a train’s DPU’s. Is this CN 0001 something like that?
Much ‘closer to home’ the ‘other’ Canadian carrier (CP) is famous for ‘robot’ midtrain control cars.
The CN idea is to provide ‘easily loaded and connected’ additional recharge, presumably at much higher volume and greater long-term reliability than a little locomotive compressor, in what may be cold weather on critical grades. I presume it also includes DPU-like ability to vent the trainpipe to accelerate both service and emergency applications. (It would not need ‘radio’ to accomplish that; the ‘shockwave’ propagating down the trainline after an emergency application would trigger further volume release to start setting up individual cars outward from the ‘container’ within the time of propagation at the effective speed of sound in the trainline – I think quicker in cold weather.
In my opinion it’s good common sense to put this in a container, adequately insulated, sledded, and shockproofed, as a great deal of deployment flexibility is realized thereby (instead of using a boxcar or old baggage car or B-unit arrangement). Nothing more complicated than a single spine underframe or single well would be needed to run it like one of the CP robots anyway. If more than one is needed in a consist … dray it in if needed and have the intermodal loading equipment drop it in for carmen (riding the dray if necessary) to connect up in a few minutes. Presumably deadhead or transfer moves (for example traffic asymmetry) can be easily handled by dropping the container on the next available space on an intermodal consist – even easier if the
On a related topic:
Has the final report on the Spiral Tunnels tragedy been released? I’m thinking not.
It will be some time yet. Probably another year, plus delays from pandemic-related work restrictions.
The TSB has also not yet released their report on another runaway (without injuries or fatalities, so it didn’t make the news) caused by air brake failure, which happened on CN a year before the fatal CP incident.
I am very curious to see what the findings will be.
That train had been in emergency. All the brakes should have been fully applied, right? I also read that 84 retainers had been deployed, but I’m a bit foggy on how much (or even if) that would affect a standing train.
Isn’t low pressure in the brake reservoirs the only possible culprit? Does severely cold weather cause much more leakage than usual? If so, why? IIRC the train had been sitting there for three hours.
Could the reservoirs have been low on pressure from a brake application shortly before the final stop where the crew change happened, and the first crew never let the engines pump the reservoirs back up? (seems highly unlikely to me) Am I remembering correctly that no hand brakes had been applied?
I’ll go back and read the threads here on this.
Freight car air brake control valves are direct release. They cannot be partially released, and the reservoirs cannot be recharged without releasing the brake application. The retainer is located at the end of the exhaust pipe from the brake cylinder, and when set to the “high pressure” position it will keep some air pressure (~20 PSI, about the same as a minimum application of the automatic brake) in the brake cylinder. The other position on the retainer, “slow direct”, allows the brake to release completely but takes a longer time to do so. The purpose of this position is to allow the train to be recharged ‘on the fly’, without stopping.
I work for CN, not CP, so obviously have never been on the Field Hill. But in my experience working on other mountain grades a minimum application of the automatic brake would probably not be enough to hold a loaded train stationary on a grade of over 2%.
I suspect the rationale behind CP’s policy at the time was to allow for the train to start down the grade while being held back by a combination of dynamic braking and the limited braking effort provided by the retainers. Ideally, the train would accelerate slowly enough that it would regain enough of a charge to be controlled by the time it attained 10 mph.
But there is no guarantee this would occur, especially on a bitterly cold night with a train that had already exhibited braking problems.
[quote user=“Lithonia Operator”]
Isn’t low pressure in the brake reservoirs the only possible culprit? Does severely cold weather cause
Trains had a short article on theose cars sometime (IIRC) in the latter half of the 60’s. Stated reason was to reduce the time to pump up the air in cold weather as it could take a better part of an hour without the cars to assist.
When I was a kid (1950’s), and my Dad was a Trainmaster, I can recall numerous occasions when he got mad as some train or the other pumped air for the entirety of the Hours of Service woking time and still weren’t able to create enough pressure on the caboose to be able to leave the terminal on bitterly cold nights in Northern Indiana.
One thing that wasn’t common in those days were air dryers treating the output from the air pumps. Without dryers water vapor in the air would get turned into enhanced water vapor in the trainline - in super cold temperatures, freezing of the trainline and/or air brake valves did happen. Adding alcohol to the air pumps intake was the ‘fix’ at the time. Today’s locomotives and air sources all have air dryers in their system - alcohol is forbidden in trainlines these days.
We certainly do not want any inebriated trainlines.[:)]
In January of 1958, I rode from Chattanooga to Bristol,
Deggestry: A question that often popped up when passenger trains diverted over other routes.
Did you notice if any mail was left or picked up in either Kingsport or Gate City. ? I remember a RPO cleark telling me that those cities were sorted on the trains 45 and 46 mail cars from Chattanooga - Bristol ( PO crew change ) - WASH.
Also did you get to meet the Clinchfield or SOU RR ( applachian division ) pilot crews ?
EDIT Guess you got to transit natural tunnel. How late in Bristol ?
I’m sorry, but my answer to all your questions is “No.” The only stop made between Johnson City and Bristol, as I remember, was at Gate City, where the engine was put back in front of the headend cars–because of the track connection in Johnson City, the engine was coupled to the