- P-train: An NMBS/SNCB commuter train.
- Pacific: A steam locomotive with a 4-6-2 wheel arrangement.
- Pannier tank: A tank locomotive with the water tanks mounted on the boiler like panniers.
- Pantograph: An arm to pick up current from overhead lines.
- Paper: Colloquially, a track warrant, train order or other movement permit that is dictated by a dispatcher and copied in writing by a train crew member.
- Pennsy: 1. Abbreviation for the former Pennsylvania Railroad. 2. A nickname for the PRR's K-4 class steam locomotive.
- Per diem: A fee paid by a rail company to the owner of a car (US) (wagon (UK)) for the time it spends on the company's property; also an authorized living expense payment for some workers forced away from their home terminal. Pronounced by some U.S. railroaders per die-um, not per dee-um.
- Permissive signal: a block signal whose most restrictive indication is stop and proceed. A permissive signal is identified by the presence of a number plate affixed to the mast or supporting structure. Proceeding beyond a permissive signal at stop is allowed at restricted speed if operating conditions enable a train operator to stop before reaching any train or obstruction.
- PICOP (UK): Person In Charge Of Possession – the railway or contractor's official responsible for safe working during engineer's possession.
- Pilot engine (UK), Helper (US): The leading locomotive during a double heading operation, attached in front of the train engine.
- Piston: The moving component in the cylinder of a steam engine or internal combustion engine that translates into motion the force exerted by pressurised steam or exploding fuel.
- Piston travel: A specified distance that a brake piston may move from its cylinder to the brake rigging. If the travel exceeds or falls short of this distance, the equipment must be set out for repair.
- Point machine (UK): A motor or device which operates points.
- Points (UK): switch (US). Also "turnout".
- Pony truck: A two-wheel truck (US) or bogie (UK) at the front of a locomotive.
- Porch: Usually on U.S. locomotives, it is the extended walkway at either end of a locomotive. Can either be long or short, depending on the buyer's specifications.
- Porter: A Porter had various roles: A Baggage Porter assisted with luggage; an Operating Porter assisted with Safeworking duties; a Station Porter assisted with general station duties and a Lad Porter was a junior Station Porter.
- Position light signal: A block signal in which the position of the lights determine the meaning of the aspect shown.
- Pound (rail): Term describing the weight (and thus the cross section) of a length of rail. A heavier rail can carry heavier loads with less distortion and less damage to the rails themselves and the roadbed.
- Power: A slang term referring to a locomotive or group of connected (MU'd) locomotives serving as the motive power for a train (as in "the hostler brought the power to the service pit.")
- Power braking: Pulling against the train brakes at the higher end of the locomotive's power output (e.g. notches 5 through 8 on a conventional throttle); this is considered wasteful of fuel and brake shoes.
- Prairie: A steam locomotive with a 2-6-2 wheel arrangement.
- Prime mover: The internal combustion engine of a diesel locomotive.
- Pull-apart: A rail broken from cold-related contraction.
- Push pole: Push pole about 12 feet (366 cm) long and having a diameter of 5 inches (127 mm). They were placed in receptacles called push pole pockets. The pole was placed between the locomotive and the freight car, and used to push the car on or off a siding or to another track. Used between 1870 and the mid 1960s.
- Push-pull: A mode of operation whereby a locomotive-hauled train may be driven with the locomotive at the front, middle or back of the train. Also: Auto train (UK), above. See Top and tail for train with locomotives at both front and back.
(US) Also referred to as DPU, or Dispersed power unit, it is designed to even out power or weight put on one locomotive. Usually this is used in steep grades for the uneven weight and braking. With DPU's, it allows braking at both ends and power.
|
|