Consist Separated By Load

[wb2002]

Real Life - I can understand how consist work with cable on locos that are directly attached to one another but how are engines synchronized to perform with lead engine separated by cars - some even in rear of long loads?

wb2002

[bapguy]

look here.  Joe
https://en.wikipedia.org/wiki/Distributed_power

[jward]

in some cases, there are different crews running the locomotives at the front and rear of the train. they use radio communications to keep each other informed of changes in throttle settings, air brake use, speed, etc.

[RAM]

live crew is for helper locomotives.  They are for the short haul. 10 to 30 miles.  DP is used for the long hauls, say  Chicago to LA.

[jward]

around here the helper district is about 120 miles, Altoona to Pittsburgh. we have some crews that operate with a manned helper on the rear for 80% or more of their runs. dpu seems to be a preference by railroad more than a distance thing. western roads prefer dpu, and it is relatively rare on the eastern ones.

[J3a-614]

All that has been described so far has been for the modern age.  

What may be of interest was how this was done in the steam era with no radios and no multiple unit control.

The answer was a combination of whistle signals, experience, feel, and an eye on the air brake gauges.  

As an example, the Norfolk & Western had a famous pusher grade of about 11 miles or so from Boaz (also called Bonsack) to Blue Ridge, Virginia.  Routine was the two road locomotives, often a team of a class A and a class Y6 of some sort, would roll past the helper pocket and come to a stop with the caboose a short distance ahead of that location.  Experience played a role in this, considering a typical train of 175 hopper cars would be well over a mile long.  

At this point the helper would come out of the pocket and couple on.  Once the air was tied in and the pressures equalized, and the engineer on the helper placing his air brake valves in the double-heading position (allowing the lead locomotive to control the brakes on the pusher), the engineer on the helper would sound a long single note on the whistle.

Once the sound made its way to the head end, the lead engineer would place the brakes in release, watching the air gauge rise.  

At the rear of the train, the conductor in the caboose would also be watching the air gauge there, and at a certain point would open his emergency valve, causing a brake application, then close the valve.  This would cause a pressure drop visible in the cabs of the lead and pusher engines, followed by a pressure rise as the brakes went back into release.  It was on this second pressure rise that both lead and pusher engineers would open their throttles and start the train into motion.  

For the next 11 miles it was a drag up the hill, the engines working in one of the most spectacular steam shows in the east.  

At the top of the hill, the rear brakeman would be riding the trailing platform of the caboose.  From this position, he would first close the angle cock on the caboose with an extension handle, then pull the pin.  On a signal to the helper engineer, the helper would shut off, and uncouple on the fly.  There are variations on some of the techniques used at this time; some have written that the angle cock on the pusher's pilot was left open, letting the locomotive go into emergency to stop, but there is also video footage that suggests the pusher was stopped under the control of the engineer.  

Once the pusher engineer observed the train proceeding and had stopped his locomotive, he would await a clearance to back down the hill (under CTC authorization in later years, under standard clearance or orders in earlier times), where the helper would go back into the pocket to wait for another train.  

Service facilities in the steam era at a pusher station like this could range from just a water tank (Boaz, which wasn't too far from Roanoke, engines returning to there with their crews after a shift), to a tank and a coaling facility (the latter might be just a spur with a gondola and a bunch of laborers to shovel the coal into the tender, as was the case for the C&O at Limeville, Ky.), to a complete locomotive facility with water, coal, sand, ash pits, and a running repair shop (Rowlesburg, W.Va., on the B&O).

The practice of coupling the pusher behind the caboose was something that would typically be done only with steel or steel framed cars.  Wooden cabooses, or railroads with management that was more conservative, would have the pusher cut in ahead of the caboose, which required switching at both ends of the hill.  

In the steam era it was also fairly common to turn the pusher at the top of the hill so it was headed in the right direction for the run down.  This of course would require turning facilities at both ends of the grade as well.  This was normally done if the grade was long enough that the time savings of faster running forward down the hill would justify the expense and extra time to turn the pusher.  Examples of this included the Alleghany grade on the C&O (Hinton, W.Va. to Alleghany, Va.. a distance of 50 miles), and Roseville to Norden, Ca. on the Southern Pacific (a similar distance, as I recall).  

As might be imagined, in steam such operations would be noisily and smokingly spectacular.  One of the best shows would have been the Western Maryland's now abandoned Blackwater Canyon line between Elkins, W.Va. and Thomas.  Here was a railroad with grades as steep as 3% and curves sharp enough to prevent the use of cars over 70 feet long.  This meant power was restricted to very large 2-8-0s (about 150 tons) with big 12-wheeled tenders, but even this very impressive power was limited to 10 loaded hoppers on 3%--and the railroad ran 100 car trains up this hill.  Yes, that meant ten locomotives per train, three forward, four in the center, and three more at the rear!  I'll let you imagine the noise and also the smoke; one railfan, photographing this operation in the 1950s, noted that the lead engines so smoked up the canyon that he almost didn't have enough light to photograph the mid train helpers (the smoke just cleared in time).

At Thomas the rear end pushers, the mid-train helpers, and the lead helper would all be cut out and turned for the return to Elkins, leaving only two engines of the ten to take the train the rest of the way to Cumberland, Md.

It's no wonder the WM was also known as "Wild Mary!"

[jward]

some clarifications on the blackwater canyon operation, which I was privileged to witness firsthand in the diesel era.

while overall the grade up the canyon was about 3%, there was a short stretch of 4% coming out of big run curve. big run curve was the sharpest on the line, at 20 degrees, and its sharpness precluded the use of 6 axle diesels. it was about 3-4 miles from the bottom of the grade, after any momentum gained on the approach to the canyon had been lost, and even so it carried a 10mph speed restriction. the train would "bind up" in the curve right when the locomotives would be on the 4%. this is probably one of the big reasons that helpers were cut into the middle of the train. mid train helpers were not common in the east, except for southern railway's remote controlled ones.

Thomas was not the top of the grade. the actual summit was several miles east at Fairfax. however the grade lessened once the rails exited the top f the canyon, and it was only about 1% from there to Fairfax. standard operating procedure was to cut out the mid trains at Thomas, and continue on to Fairfax with just the head end power and rear helpers. sometimes the mid trains would grab some empties out of the Thomas yards for a short run up the francis spur while waiting for the rear helpers to return to Thomas. usually both sets of helpers would couple together and return to elkins as ne move, this was done for safety reasons as this was unsignalled territory.

occasionally, there was more coal at elkins than could be moved in one train. in this case, the helpers would return partway to elkins and meet the second train for a repeat performance. to complicate matters, during my time observing this line, the trains were run as turns to bayard, about 20 miles beyond Thomas, so they had to find a place to get loaded and empty trains around each other. Thomas had a passing track, as did Hendricks at the bottom of the canyon, so those would have been the most likely meeting points.

ain't railroading fun?

[rogertra]

My experience with steam helpers, although in the UK in the 1960s, was engines communicated with each other, when starting, using whistle signals, in the UK they called it "crow" whistle (There was no equivalent of rule 17 (whistle signals) in the UK).

The helper engineer then worked the engine, as J3a-614 says, through experience.  In effect, he ran the engine as though he was driving the train on his own just keeping an eye on the brake gauge.  A bit tricky in the UK where many freights were "unfitted", in other words, no brakes.  Just the engine brakes and the brake van (caboose) brakes.  Locally, engineman used their own whistle signals that were learnt through being a fireman.  In the UK, you'd start as a "cleaner" (wiper), say around 16 years of age and wouldn't become a fully qualified "driver" until your early to mid 30s and not get to drive the top of the line, freight and passenger trains and therefore the best paying jobs. until near retirement age.

Cheers

Roger T.

[wb2002]

Thanks to all for expressing your knowledge and experiences. I would think that because of the amount of slack that existed within the couplers , which should be compounded/reduced by the number of cars , would create a problem if the lead loco was not  somewhat perfectly synchronized with the mid/end locos.

This leads me to another question that comes to mind. Has there ever been an accident/derailment caused as a result of consist separated by cars?

wb2002

[jward]

slack is a major problem. it is more so on helperless trains. with helpers, slack cn be controlled by having the helper keep the slack bunched in the train.  good example of this is the Altoona helper pool on the ns former conrail line. westbound trains need a boost up the mountain out of Altoona to gallitzen, as the grade is 1.8% for about 12 miles. once over the top, nd particularly west of Johnstown, they encounter a series of short 1% grades both u and down. without helpers, the train is whipsawed by slack as the train goes over these grades. with helpers keeping the slack bunched, broken couplers are all but eliminated.

[RAM]

That ups & downs is where skill of the engineer comes in.