tops

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (March 2008)

Total Operations Processing System, or TOPS, is a computer system for managing the locomotives and rolling stock (railroad cars) owned by a rail system. It was originally developed by the Southern Pacific Railroad and was widely sold; it is best known in the United Kingdom for its use by British Rail.

Early development

The Southern Pacific Railroad was ahead of the pack in its embracing of technology. In the early 1960s it developed a computer system called “Total Operations Processing System”, or TOPS. The purpose was to take all the paperwork associated with a locomotive or railroad car - its maintenance history, its allocation to division and depot and duty, its status, its location, and much more - and keep it in computer form, constantly updated by terminals at every maintenance facility.^[1] On paper, this information was difficult to keep track of, difficult to keep up to date, and difficult to query - the only way to do that would be a whole lot of phone calls. Computerising this information enabled a railroad to keep better track of its assets, and to utilize them better.^[1]

One way to offset the development costs of such a system, of course, was to sell it to other railroads, and the Southern Pacific did just that. A fair number of American railroads took to the system, as did many others around the world.

Adoption by British Railways

In the mid to late 1960s British Railways (soon to be rebranded British Rail) was searching around for ways to increase efficiency, and came across the TOPS system being used by the Canadian National Railway. They purchased the system (along with source code, as was typical for such a large mainframe-based system in those days) and slowly implemented it. At the time, the British Government operated a "Buy British" policy for the nationalised industries, and the purchase of an IBM 360 mainframe to operate TOPS had to be approved by the Cabinet of Prime Minister Edward Heath.

The adoption of the TOPS system made for some changes in the way the railway system in Britain worked. Hitherto, locomotives were numbered in three different series. Steam locomotives carried unadorned numbers up to five digits long. Diesel locomotives carried four-digit numbers prefixed with a letter 'D', and electric locomotives with a letter 'E'. Thus, up to three locomotives could carry the same number. TOPS could not handle this, and it also required similar locomotives to be numbered in a consecutive series in terms of classification, in order that they might be treated together as a group.

TOPS numbering

Brush Type 2 locomotives became Class 31 under TOPS. This is the data panel from a Class 31/4; the 31/4 subclass being used for locomotives with Electric Train Heating.

Sequentiality was all that was required, but with the requirement to renumber, it was decided to adopt a logical system for classification, and the five- or six-digit TOPS number was divided into two parts. No class of locomotive or multiple unit numbered over 1000 examples, so the last three digits were used for the individual number between 001 and 999 in that class. The first two or three digits were used to denote the class of locomotive or multiple unit. The numbers were often written in two space separated groups, such as '47 401' to highlight that division, but the TOPS system actually stored and displayed them without the space: '47401'. Sub-classifications were indicated in the TOPS system with a slash and a subclass number, e.g. '47/4'. It was convention — though not enforced within the TOPS system — that subclass numbers were boundaries in the locomotive numbering system, such that class '47/4' started with number '47 401'. If there were more than 99 numbers in a subclass, the number series extended to the next value of the third digit; thus, since there were more than 200 locomotives in class '47/4', subclasses '47/5' and '47/6' did not exist, and the next valid subclass by convention was '47/7' starting with '47 701'. However, in some cases, the sequences do not match, e.g. 158/0 numbers start at 158 701.

Locomotives are assigned classes 01–98: diesel locomotives 01–69, DC electric locomotives 70–79, AC electric locomotives 80–96, departmental locos (those not in revenue-earning use) 97, and steam locomotives 98. One oddity was the inclusion of British Rail's shipping fleet in the system as Class 99. Diesel multiple units (DMUs) with mechanical or hydraulic transmission are classified 100–199, with electric transmission 200–299. Electric multiple units (EMUs) are given the subsequent classes; 300–399 are overhead AC units, while Southern Region DC third rail EMUs are 400–499, other DC EMUs 500–599. Classes 600–899 have not yet been used, but selected numbers in the 900 series have been used for departmental multiple units, mostly converted from former passenger units. More information can be found on British Rail locomotive and multiple unit numbering and classification.

Coaching stock and individual multiple unit cars are allocated five-digit numbers; since the early 1980s it has been forbidden for them to have the same numbers as locomotives, but before then duplication was possible because they carried a prefix letter, which was considered part of the number. More information can be found on British Carriage and Wagon Numbering and Classification.

Locomotives began receiving their TOPS numbers in 1972, while EMUs and DMUs did not receive TOPS unit numbers until later. Some locomotives that were slated for withdrawal, such as the Class 52, were classified but never actually received a TOPS number and operated until the late 1970s with their old D-prefix numbers.

Recent history

TOPS has grown very out of date in recent decades. It is a text-terminal, mainframe-driven system which is not very user-friendly, cryptic, hard to use and prone to operator error because of its cryptic displays and command set. In addition, it is written in its own programming language, TOPSTRAN (not strictly speaking a separate language but a set of IBM Assembler macros), and it is increasingly hard to find and train developers to maintain it. The division of British Rail and privatisation has also hurt TOPS, because it was never really designed for that; some Train Operating Companies do not keep information as up to date as they should.

Attempts have been made to 'skin' the system with a more user-friendly interface, called TOPS 2000; in addition, there are other parallel systems now, such as TRUST and Genius, but none has yet supplanted the TOPS system.

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.^[2]

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    888 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

References