TOPS

Total Operations Processing System, or TOPS, is a computer system for managing the locomotives and rolling stock owned by and/or operated on a rail system. It was originally developed by the American-based Southern Pacific Railroad and was widely sold; it is best known in Britain for its use by British Rail (BR) and its successors.

The main parts included: Locomotive/ Unit Numbers, Coach Numbers, Wagon Numbers, Coach Coads, Wagon Coads and Headcoads.

Sample Output
This is a typical report that a TOPS clerk could generate. The train in question is a 25 wagon freight train travelling from Over & Wharton, near Winsford, to Reading West Junction, Berkshire.

K383400 0010 2837 22/10/86 U483 ON N199 BY KO TRAIN ENQUIRY RESPONSE FOR 377Z380 22  TFA - 9KJ ACTUAL TRAIN ID 377Z380 22 BOOKED 7Z380 DEP OVER&WHAR 1520 22   2 HRS 20 MINS LATE FOR REASON L CAT B  SECTOR 5 LOCO      25901 LOCO      25908 25 LDS   0 MTYS    886 TONNES   799 T/FT  418 POTENTIAL VAC BRAKE FORCE STATION        CONSIST      ARR        DEP      LDS MTYS   SCHEDULE 37015 OVER&WHAR                        1520     025 000    71212 65700 BESCOTYD   NRP        1707 EST   1709 EST 025 000 74260 READINGWJ DETAIL      2007 EST            025 000 END

Identifying
Each locomotive and Wagon had a number and a TOPS Pannel, meaning a driver, shunter or gaurd could tell what was to make up there train. Here are some images of TOPS Pannels:

Multiple Units
Each unit was made up of a certain amount of Coaches with there individual designations. Here are the main range:

AC electric multiple units AM1-AM11 became 301-311 in order (in fact the AM1 units had already been withdrawn, so Class 301 was never actually used). The 1xx and 2xx series were originally arranged so that driving motors, driving trailers and trailer cars all had their own individual class numbers (presumably because these units were more prone to being reformed), but this was subsequently revised so that each type of unit had a single class number, as allocated to the driving motor car.

Whereas within most ranges class numbers were allocated sequentially as new types were constructed, the Southern Region adopted a more complicated system for their electric multiple units, with the second and third digits indicating in more detail the type of unit. Second digits were allocated as follows:

Third digits were allocated as follows:

Coaches & Wagons
The second letter gave more detailed information, different for each series. The tables below list the variations for carriages:

The final letter indicated the braking arrangements. Nowadays almost all stock is air-braked, but when TOPS was introduced there was much greater variety, which made marshalling trains more complicated and this information essential. The letters were: