How do pushers work?

[Ralph]

I was having some fun with my Sandpatch version of Microsoft Train Simulator, hooking up a heavy ore train with a pair of helpers on the C&O when it made me wonder how this works on the prototype. How do the front and rear locomotives coordinate their speeds to avoid too much or too little slack on the train? I imagine that radios help nowadays but how was it done before radio was available?
Ralph

 

[Vic]

Steam Days

Hi Ralph, In the days of steam it was done by whistle signals.

 

[Ralph]

That makes sense Vic! I would think pushing would take some precision. Seems to me it would be easy to shove some cars off the rails by bunching them up against the front locos....
Ralph

 

[Vic]

Pushing

Ralph, From what I've read in some of my railroad books engineers who operated in pusher and helper service had to sort of develope a "feel" for the train. In the days before radio communications between engines this was based on a lot of factors such as total tonnage, tractive effort, number of cars, visual and auditory observations, engine performance, familarity with the "road" and even weather conditions. Experienced engineers in this service could litterally anticipate each other's actions and anticipate what each other would do as they "shoved over the hill"

I've always said that running a steam locomotive was an art as it is as close to a living breathing thing as a mechanical thing can get

 

[Jaws]

Hi Ralph.

One of my treasured memories is, as a twelve year old, being allowed to sit in the cab of an older (AC-4) S.P. cab-forward. I observed the practice of the "art" of train teamwork by the man at the throttle. We were hooked onto the rear of a ninety car freight, with nothing behind us but the caboose. We were on a siding just at the start of a better than two percent grade about ten miles in length, waiting for the eastbound Daylight to clear.

As soon as the passenger train cleared, the switch was thrown at the head end. Watching the brake pressure, and receiving a signal from a brakeman standing atop a freight car, the engineer knew when to start pushing. He explained as we started that the head end locomotive was not doing anything and we would apply all the power until it was obvious more power was needed.

At that point, the head end would start pulling. Both the pushing and pulling loco operators knew from experience when to add power or slack off. The goal was to get the consist safely and gently over the grade without stalling or breaking a coupler. At an average speed of around 10 mph, (as slow as a slow walk and as fast as perhaps 15 mph) it took just under an hour to "make the grade". It wasn’t as simple as it sounds, as there were some areas where the grade was less and others where it was more. It was also essential for both engineers to monitor the brake pressure and remain alert for signals from the crew as something could always occur which would require an emergency stop.

At the summit, still moving, we were unhooked from the train and slowed until it was about a hundred yards ahead of us and the siding was clear. At that point, we poured on the steam until we were moving faster than the train. The caboose was unhooked behind us, we pulled into the siding and a brakeman threw the switch so the caboose could catch the train. This latter operation was probably the most impressive part of the whole show.

Almost as vivid in my memory is laying abed at night and listening to the trains. Their exhaust would slow as they hooked into the grade until it was often a second or more between chuffs. These articulated engines gave a “double chuff” on each stroke because of their double cylinders. The sound was “chuff (hesitate) chuff (pause) and then chuff (hesitate) chuff (pause) again.

Forgive me if I got carried away, but the subject takes me back to some of the memories that always kept me hooked on railroading.

 

[Rusty Spike]

Wow, great memories - thanks for sharing.

 

[Anachron]

That was I very nice story

 

[Ralph]

Jack, thanks for posting your story. It was very illustrative and helped answer my question. What a lucky kid you were!!!!!
Ralph

 

[spitfire]

Jack, thanks for the great story. It's always good to be reminded so vividly of the real thing!!

Val

 

[Gary Pfeil]

A question. I'm not sure how the caboose would be coupled to the train. I've heard of setting out freight cars in facing point sidings using the "flying switch" method described, with a brakeman riding the car to apply the cars brakes. A dangerous procedure outlawed at a date I'm not sure of. But how would the caboose get coupled? And the air hose connected?

Gary

 

[Tad]

Interesting story, Jack.

Thanks,

 

[sumpter250]

It was also essential for both engineers to monitor the brake pressure and remain alert for signals

Much of the engineer to engineer communicationwas done via quick variations in brake line pressure, which registered on the brake line pressure gauge.Often along with whistle signals.
In most cases the helper pushed on the caboose. On the C&O, when an Allegheny was used in helper service, the caboose was dropped, the hepler picked up the caboose, and then pulled up to the rear end of the train to begin pushing. This may have been more for the peace of mind of the crew, than for safety.
When dropping off the helper, the caboose could be "flying switched" past the helper, and then the helper could shove the caboose up to the train, or the train could be backed to pick up the caboose.
The train would be stopped, to drop the helper. The brakeman could easily couple, and connect the brakeline.

 

[Gary Pfeil]

OK, thanks for that explanation. Upon rereading the story I see I had assumed that the statement "so the caboose could catch the train" meant that it was coupled on the move, and that was what I couldn't quite get. That would be quite a trick!

 

[TinGoat]

It also

Depends on the type of Caboose.

The older Wooden Caboose would get crushed if it was pushed by the helper engine.

A stronger steel caboose was developed that could take the pressure of being pushed.

This saved time and effort of having to cut the helper locomotive inbetween the train and the caboose. The Steel Caboose allowed the helper locomotive to just come up behind and start pushing without any fancy switching manuvers.

Sometimes a helper engine was cut into the middle of the train instead of at the rear. This was the practice (rule) on many early railroads. It wasn't until stronger rollingstock was developed that it became more common for the helper to take the rear position.

I don't know the dates, but if your rolling stock is mostly wood and/or uses truss-rods and queen-posts to reinforce the frames instead of steel frames, then I'd go with cutting the helper into the middle of the train instead of pushing from the rear.

On really long trains, helper engines may have also been added in the middle of the train along with ones on the rear...