A "Block" is a group of cars that will be handled together from a location to the next place the cars are classified, interchanged, change trains or spotted at industry. The cars may be different final destinations. Blocks may be differentiated by :

  • Final destination
  • Interchange road
  • Next switching location
  • Car type
  • Industry
  • Direction
  • Next train

Blocks are identified by a block name or code:

  • Text name (Houston)
  • Alphanumeric code (HOU1)
  • Numeric code (135)

Blocks are used in classification yards to separate the cars. Each classification track may hold one or two blocks. Blocks are also used to assemble trains, a particular train sysmbol or schedule will carry only certain blocks. The blocking pattern is described in a "transportation plan" for the train. One special type of blocking, particularly used on locals, is station order blocking. The cars are blocked by the destination station and the train is assembled with the blocks in order from the front of the train to the rear of the train in the same order the train will arrive at the stations. So if a train originates at Anna and operates on the route Anna-Bess-Cloy-Dora-Eve-Fay, the train will be blocked:


It is also possible, that a train such as the one above may be blocked in the reverse manner as follows:


This will more likely be trains that run over several sub divsions where the blocks will be added and removed at crew change points by yard switchers.