TOPS codes

BR introduced the American TOPS (Total Operations Processing System) system for managing rolling stock in the late 1960s. Under TOPS, every item of rolling stock was required to have a unique ID and and was allocated a classification code.


TOPS classification

TOPS locomotive classification and numbering

BR steam had finished before the introduction of TOPS. BR Diesel locomotives were allocated numbers forming the unique ID in the form xxyyy, with xx being the class and yyy one of up to 999 members of it, for example 50031 Hood would have been the 31st Class 50 locomotive while in service.

Heritage diesel locomotives working on the main line are allocated numbers in the 89yyy series. Generally the third digit represents the power classification and the final two digits are the last two digits of the pre-TOPS number, except where duplication occurs (for example D1015 was allocated TOPS number 89416 because 89415 was allocated to 50015/D415 Valiant). TOPS numbers allocated to SVR locomotives include:[1]

45110 cab interior showing the TOPS number used in preservation
Heritage steam locomotives working on the main line are allocated numbers in the 98yyy series. Generally the third digit represents the power classification and the final two digits are the last two digits of the BR era number, except where duplication occurs. TOPS numbers allocated to locos resident on the SVR include:[2]

For heritage locomotives, the TOPS number was used for reporting purposes and was commonly displayed inside the cab.

Heritage carriages used on the main line are allocated numbers in the 99yyy series. The SVR's GWR main line set were allocated the following TOPS numbers:[3]

TOPS carriage and wagon classification codes

TOPS classifications were applied to all carriages and wagons and recorded in a field called CARKND. For most rolling stock the classification comprises three letters, the first letter indicating the broad type, the second letter giving more detailed information of that type (different for each series) and a suffix giving the braking arrangements. The last was an important aid to marshalling trains at a time when BR had a mixture of air, vacuum and other braking arrangements.[4]

Passenger carrying stock (type A) included a digit after the first two letters to specify the class of passenger accommodation (1=First, 2=Second, later Standard, 3=Composite, 4=Unclassified, 5=None). The suffix indicated the build rather than the braking arrangement (1=Mk 1, Z=Mk 2, A=Mk 2a, etc.)[5]

Examples of the main classification codes (first letter) after 1984 were:

  • A: Hauled passenger carriages
  • B: Bogie Steel wagons
  • C: Covered bulk wagons (except CA: goods brake vans)
  • D: Diesel Multiple Unit carriages
  • F: Flat wagons
  • H: Hopper wagons
  • M: Mineral wagons
  • N: Hauled non-passenger carriages
  • O: Open wagons
  • Q: Hauled departmental (non-revenue) carriages
  • S: 2-axle steel wagons
  • T: Tank wagons
  • V: Vans
  • W: Flat wagons
  • Y: Departmental bogie wagons
  • Z: Departmental two-axle vehicle (carriage or wagon)

Examples of braking codes (third letter) were:

  • A: Air brake only
  • B: Air brake plus through vacuum pipe
  • O: Unfitted (handbrake only)
  • P: Unfitted with through vacuum pipe
  • Q: Unfitted with through air pipe
  • V: Vacuum brake only
  • W: Vacuum brake plus through air pipe
  • X: Dual brake (air and vacuum)

SVR rolling stock with TOPS classification codes

Note: Most of the GWR / LNER / LMS era rolling stock had been withdrawn by the time TOPS was introduced in the late 1960s and would therefore not have received TOPS classification codes. Later SVR rolling stock with TOPS classification codes includes:


TOPS classification Description Examples
Mk 1 Passenger carrying stock (prefix A)
AA21 Corridor second

Operational: 25346, 25498, 25771
Staff accommodation: 24839, 24845, 25594, 25686

AA31 Corridor composite 16169, 16202, 16267
AB21 Brake corridor standard 34562, 34606, 34754, 35219
AB31 Brake corridor composite 21254
AC21 Tourist standard open 4345, 4399, 4505,

4545, 4550, 4593, 4690

AD11 First open 3083, 3103, 3109
AE21 Brake standard open 9220
AJ41 Restaurant Buffet 1667, 1682
AN21 Restaurant Miniature Buffet 1853, 1855, 1856
Mk 1 Non-Passenger carrying stock (prefix N)
NAV Brake gangwayed 80776, 81013
NJV GUV (ETH wired) 94157, 94200 (as built)
NKA GUV (BRUTE) 94157, 94200 (as rebuilt)
NKV GUV (BRUTE) 86105, 95154 (as built)
NNX Courier Van with dual Vacuum / Air braking 80222
NOx GUV 100mph 95154 (as rebuilt)


TOPS code displayed on 'Seacow' DB980239
TOPS classification Description Examples
Private-Owner Bogie Wagons (prefix J) (from 1990)
JGV Bogie Limestone Hopper (TOPS code PHV before 1990) ICI 19052, ICI 19129
Mineral wagons (prefix M)
MCO 16t Open Mineral Wagon (unfitted) 118443, 257698
Vans (prefix V)
VAA 29t Vanfit (full length doors, ventilated), air braked 200176
VCV Cattle van, vacuum braked 891054
VDA 29t Vanfit, air braked 201056
Exceptional and Special Purpose Vehicles (prefix X)
XDV FLAT ED 906811, 906825, 906830
Bogie Departmental Wagons (prefix Y)
YGA/YGB 'Seacow' Bogie Ballast Hopper 6 x Seacows
YLO 'Gane A' Bogie Rail Wagon 996730
YNO ‘Prawn’ Borail/Bolster Wagon 997623
YQA 'Parr' Bogie Rail Wagon 967526, 967577
2-axle Departmental Wagons (prefix Z)
ZBA ‘Rudd’ (also Carp/Hake) Ballast Open 15 x Rudds
ZCO ‘Tunny’ (and other) Ballast/Sleeper Open 991124
ZFV 'Dogfish' Ballast Hopper 983115
ZJV ‘Mermaid’ Side-Tipping Ballast Wagon 989098
ZMV ‘Mackerel’ Ballast Hopper 992329
ZUB ‘Shark’ Ballast Plough Brake Van (Vac fitted) 993876
ZUV ‘Shark’ Ballast Plough Brake Van (Air braked) 993898

TOPS location codes

See also