California's Railroad to the U.S. 1861 - 1996

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Model Train Help EBook

(c) Bob Dengler RAC #263 and another at Roseville

Western region Timetable #14

Effective Sunday October 28, 1979

Special Instructions - All Subdivisions

Rule 20. REPEATER AIR CARS (RAC) SP 260 thru 266.

see also: Repeater Air Car Detail Images

(C) Todd Montgomery 1976 - RAC 260

The repeater air car is utilized to increase efficiency of train air brakes on long trains and during cold weather. The purpose of repeater relay equipment is to accept pneumatic signals from the brake pipe of forward portion of a train, and by relay action, produce a corresponding response in the brake pipe of the rear section of the train.

(C) John Rodgers - RAC 261

The repeater relay car has the ability to produce faster train charging time, reduce or eliminate brake pipe pressure gradient, more uniform braking forces, and faster brake application and release times.

(C) John Rodgers - RAC 263

A. Procedure for adding Repeater Air Car to a train to use Repeater Car Air Equipment.

(C) John Rodgers - RAC 264
  1. Place as near to center of train as makeup will permit.

  2. The RAC car is operational in either direction. The front brake pipe must be coupled to the portion of the train to which the road engine is attached. The rear brake pipe must be coupled to the other end of the train.
    The angle cock on the unused brake pipe on each end of the car must be closed.

  3. Where repeater air car is positioned in train and front and rear brake pipes have properly connected and opened, then close the brake pipe bypass cock No.1 and open the two repeater relay cut-out cocks Nos.2 and 3, all located inside of car.

(C) John Rodgers - RAC 265
(C) 1998 - Rob Sarberenyi, SP Repeater Air Car #266 at San Jose, 1986

Note: If for any reason it becomes necessary to transfer control of air brakes to the helper engine located in the portion of the train behind the RAC car with the RAC air equipment in operation, the brake pipe hose connections must be changed. The forward brake pipe must he coupled to the portion of the train having the brake valve which is controlling the train. The rear brake pipe must be coupled to the other end of the train.

  1. The repeater relay valve No.5 is a variable valve and is employed to reestablish a satisfactory brake pipe pressure on the rear portion of train. A regulator and gauge to indicate pounds of differential is provided. Trainline pressure on rear portion of train must not be increased above 90 PSI at RAC car. Preferred adjustment is to have the rear brake pipe 1.5 to 2 lbs. above the front brake pipe.

B. Procedure for cutting the RAC car out of train.

  1. Close the repeater relay cut-out cocks Nos.2 and 3.

  2. Open the brake pipe bypass cock No.1 All located inside the car.

  3. The car diesel engine and compressor are to remain running except during layover time.

C. Procedure for adding Repeater Air Car to a train when Repeater Car Air Equipment is not to be used.

  1. Close the repeater relay cut-out cocks Nos. 2 and 3.

  2. Open the brake pipe bypass cock No. 1 All located inside the car.

  3. Forward brake pipe must be coupled to portion of the train to which the road engine is attached.
    Rear brake pipe must be coupled to the other end of the train. The angle cock on the unused brake pipe on each end of the car must be closed.

D. Train operation of Repeater Air Cars.

  1. With the repeater air car in operation, proceed with terminal air test as prescribed in the air brake rules and regulations.

  2. All rules outlined in the air brake rules and regulations governing train handling shall be adhered to while repeater air car is part of any train.

  3. If required, the repeater air car may be cut out by closing the repeater relay cut-out cocks Nos.2 and 3 and opening the brake pipe bypass cock No.1 All located inside car. This provides for normal train operation without the repeater relay equipment operating.

  4. If yard air is used to charge the train, it must be cut in ahead of the repeater air car.

  5. The RAC car must not be kicked, dropped, or humped.

  6. During a pickup or setout, or at any time the engine is separated from the train and the air car is in operation in the train, it is absolutely essential that the trainline angle cock be left open on the train.

E. Loss of main reservoir air on RAC car.

  1. The depletion of main reservoir air to below 100 lbs. will initiate a service brake pipe reduction in the forward and rear portions of the train.

  2. When main reservoir pressure drops below 110 pounds, a radio signal will be initiated and will transmit a series of short beeps for a period of approximately ten seconds and then cease. It will reset itself automatically upon an increase of main reservoir pressure above 110 pounds.

  3. If in power, throttle must be reduced to idle and automatic brake valve placed in full service zone until train stops.

  4. If in dynamic braking, automatic brake valve must be placed in full service zone and dynamic braking lever handled as prescribed by rules.

  5. Train must be immediately secured before determining reason for main reservoir air depletion.

F. Setting RAC car out of train.

  1. If it becomes necessary to set RAC car out of train, shut down compressor engine in car and secure car per rules.

Instructions for starting and shutting down compressor engine posted inside of car.

Information compiled from postings to various SP Mailing Lists:

7 cars in total.

260 697014B-70-2
261 672385 B-70-1
262 673661 B-70-6
263 673652 B-70-6
264 673575 B-70-6
265 673260 B-70-6
266 672429 B-70-1
info courtesy Steve Peery via Joe Strapac

All put in service between November 1975 and March 1977

From Lee Gautreaux's website: the The B-70-1 and B-70-2 were 70 ton capacity 50'-1" insulated box cars all built to the same basic design by PC&F in 1959-1960 and featured 9'-0" Youngstown plug doors, Hydra-Cushion underframes, Car-Pac loaders or Compartmentizers and 4644 cu.ft capacity.

It has been reported that (at least) one had a red rotating beacon. None of the photos 'we' have here, show any evidence of a beacon. The red rotating beacon indicates that the main reservoir had depleted to under 100 lbs. This would initiate a service brake pipe reduction which would require the train to come to a halt until the problem could be rectified! At least that is what the rulebook says.

It may be that no two cars were alike, or that modifications were made due to experience...
John Rodgers peeked inside one of these cars and remembers a large air duct leading from the box to either the diesel engine or the compressor, which was located in one end of the car. He seems to recall that most of the rest of the car was empty.

Tony Thompson's photos of SP 260's interior show clearly that there was no duct at either end of the car leading up to the roof boxes (which, incidentally, were square or close to it, with louvers on all four sides and fairly open screen on top). A very large Ingersoll-Rand compressor and diesel are in one end, while the other end contains what look like regulators and surge tanks. The diesel exhaust appears to be ducted to a couple of the side louver panels. The roof boxes are not connected to anything. Whether this was true of the other repeater cars, I don't know.

The Roof vent boxes were also of different comfigurations: One of the boxes in John Rodger's images has a solid cover on top as opposed to a screen, yet the image of SP 264 clearly has screens on both boxes, as well as screen on the sides. SP 265 has a box with screen on the side and louvers on the end.

Considered opinion is that the cars were originally painted Lark Dark Gray, it has been reported some were painted a dark green in later years. Other colors reported are Medium blue, green and various shades of gray. Color perception and color shift in photos, and then scanning being what it is, most of the photos shown here appear various shades of gray. Depending on the formula of the paint, the light, age and condition of the paint, gray can shift to any of these colors.

Operationally, they were reported in:

  • Eugene, Oregon.
  • Sparks, Nevada.
  • Roseville, California

If you would like to model one and cannot justify one in a train, then maybe this will give you an excuse:

The Air Repeater Car (#261) near the 4th Street Station (San Francisco), was put there originally while the depot's air compressor system (for charging the air in the trains of cars at the platforms) was down for repairs. Afterward, it was just kept there for backup, since the repeater cars were no longer being used on mainline trains.


  • Tony Thompson
  • Brian Jennison
  • Jim Bence
  • Ken Harrison
  • Mark Miller
  • Thom Anderson
  • Don Jewell
  • Rob Sarberenyi
  • Bob Allessi
  • John Rodgers
  • Steve Peery via Joe Strapac

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