Common Railroad Terms

Like any industry, railroading has its own terminology and on this page you’ll find some of the more common terms you’ll hear from railroaders…. This page is updated as I learn more and for a detailed list check out

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Bend The Iron: Align a switch.

Communication Interrupt: Is a term used in DPU (Distributed Power Unit) operation and is theĀ intermittent loss of the telemetry signal to the DPU locomotives.

CTC: Centralized Traffic Control.

DP (Distributed Power): Distributed power are locomotive(s) placed at the rear or at midpoints of a train or both. Not to be confused with helper locomotives which are added to “help” move heavy tonnage, usually over grades. DPUs are typically used for super long trains (usually exceeding 10,000 feet) to prevent derailing and/or exceeding the draw-gear strength.

Other benefits of DPUs are minimizing run-in and run-out of coupler slack throughout the train as well as reduced draft forces along a train which in turn reduces the lateral force between the wheel and rail on curves, thereby reducing fuel consumption and wear on various running-gear components.

Faster braking is another benefit of DPU. When all of the brakes are at the front of a conventional train, it can take several seconds for pressure changes to spread to the rear. Under distributed power operation, the brakes are set at remote locomotives simultaneously with the command initiated on the lead locomotive, providing more uniform braking throughout the train.

Joint Occupancy (J/O): The term “J/O” or “Joint Occupancy” is usually associated with Maintenance of Way (MOW) personnel and simply means that one person and/or group has the permission to work in a block of railroad with another person and/or group.

When a track warrant and/or track authority is issued for a section of track, no other trains or “rail-riding” personnel are allowed to work that section of track without permission. Example: A maintenance crew is doing some welding between mile marker 671 and 672 and they have a track authority that prohibits any other “rail” activity in that section. However a Hi-Railer could “J-O” with the welding crew and the two groups could work simultaneously between 671 and 672 (with the permission of the crew that has the track authority, in this case the welding crew).

How J/Os work can vary from railroad to railroad.

Key Train: A “Key Train” is a unique train by some special circumstance. Key trains are usually associated with hazardous materials a.k.a. “hazmat.” Hazmat can usually be associated with tank cars and bulk liquids such as ethanol, crude oil and chemicals.

OCS: Occupational Control System.

PTC: Positive Train Control.

Push/Pull Operation: Not to be confused “Top and Tail operation”, push/pull operation (usually associated with passenger and/or commuter trains) is a train that has a locomotive on one end and non-powered engineer’s “quarters” on the other end allowing the engineer to control the train from either end.

RTC: Rail Traffic Control.

Service Stop: A simple railroad term for bringing a train to a safe, controlled stop.

Shoving: “Pushing” cars as opposed to pulling them.

Step On/Step Off Crew Change: A “step on-step off” crew change is a crew change that takes place when one train crew replaces another train crew on-the-spot as opposed to the train being tied down while a replacement crew shows up.

Stretching Out: The slack action of a train when it is being “pulled.”

Tie Down A Train: Tying a train down simply means parking a train for a set period of time. Think of tying down a train like setting the “Parking Brake.” It’s usually what they’re doing when you see train crews tightening the brake wheels on locomotives and freight cars (handles on older locomotives). In most cases, when a train is “tied down” it’s because the train will be left unattended.

Top & Tail Operation: Not to be confused with “Push/Pull operation”, top and tail operation is when you have locomotive(s) at both ends of a train.

Track Warrant/Track Authority: A “Track Warrant,” sometimes called a “Track Authority” depending on the railroad is a means of dispatching trains in non-signaled territory. A thorough explanation of their use can be found at