Pacemaker Freight Car (AB-1-B) Air Brake Equipment

Does anyone have any knowledge of, or access to information provided T&E Crews operating solid trains of this equipment. Were there Special Instructions, Bulletins, Road Foremans Instructions, or Timetable Instructions?

This equipment was designed to be operated in solid consists at train speeds in excess of those authorized for Freight and still be able to be controlled in the short block distances encountered on the NYC.

Would appreciate any information that the company provided its employees as to the proper handling of trains with this equipment.

I don't have a TT for that period
but here is how you could operate.
Maybe someone will have a TT.
At that time the track speed may have been 60 mph.for freight.With
the AB brakes braking was not a problem because these cars were not
heavy.As to the one mile apart signals NYC signals were based on speed and if you operated according
to signal indication this was not a problem.You are probably correct
about these trains in the TT.Just as the Van trains speeds and other
restrictions are in the TT. MEL

I never saw a timetable special instruction for it, except for higher authorized speeds. I think it was covered in the progressive examination for enginemen and hostlers, and in the Special Instructions for Air Brakes, Train Signals and Train Heat.

A train of solid AB-1-B brake-equipped cars could be operated at higher speeds if they had the air signal line connected and charged through the train. Pressure in the air signal line indicated to an AB-1-B brake that it was in passenger service, and it automatically switched over from direct to graduated release. That way, the brake could be applied with a heavy application at high speed, and graduated off as the train slowed to avoid sliding the wheels. Passenger car brakes work that way, but the valves have to be individually set for graduated or direct release.

Freight brakes without the -1-B suffix are all direct release, where a slight increase in brake pipe pressure causes a complete release. ABD brakes with accelerated emergency release will put a small amount of air from the emergency reservior back into the brake pipe to acclerate the release back through the train.

NYC had a restriction on graduated release in long trains. I think that all cars behind 40 had to be conditioned for direct release, even in mail and express trains.

Are you certain this equipment was capable of Graduated Release? It's my understanding that when the signal pipe is charged, the Emergency Portion of the AB-1-B eliminates the operation of controlled emergency and permits the emergency rate of brake cylinder build-up corresponding to passenger train operation. The shorter braking distances were obtained with a Quick Service Valve (A-2-A) that furnished quick service on each service reduction, not just the first reduction which is the case with freight equipment. I let my 1st 2nd 3rd Series Exam Book get away from me over the years so can't document my thinking. Would appreciate knowing how graduated release was possible without an additional (Auxilliary) Resevoir. Have been an RFE/Engineman for 38 years and am still willing to learn; any advise or help is appreciated in undertstanding this unique Car Control Valve.

No, I'm not certain, and I stand corrected. I successfully avoided that equipment, so all I knew was what I was told that the "air signal pressure conditioned the brake for passenger service." It was my erroneous conclusion that the "conditioning" meant that it was set up for graduated release. The only thing you get extra from the AB-1-B with the signal line charged is the succssive quick service reductions from the A-2-A valve, and nullification of the controlled emergency feature.

The only mention of special instructions that would have applied to Pacemaker cars that I can find in my stuff is in Timetable No. 69, April 30, 1950 of the Mohawk - Hudson Division. Trains NC-1, BN-2, BB-1 and BB-2 with 60 cars or less were permitted 65 mph over most of the division between Cold Spring and Kirkville (subject of course to local restrictions) where the maximum speed for other freight trains ranged from 45 to 60, depending on trailing tonnage. By 1959, before the solid Flexivan trains, all freight trains were restricted to 60 mph max with no reduction for trailing tonnage. The additional restrictions for trailing tonnage might have been lifted after K brakes were outlawed in interchange, but that's only a guess.

Thanks for sending me back to the books.

Thanks for your help; sure would like to see any instructions the company furnished for T&E people.