British Rail TOPS first arrangement
At the end of the 1960s, British Railways adopted the Total Operations Processing System, a computerised system developed by the Southern Pacific Railroad in the United States. All types of locomotive and multiple unit received a TOPS classification, but the first attempt at applying TOPS was soon modified. This page explains the first attempt at using TOPS and cross-refers the classes allocated with those adopted in the successful re-arrangement. An explanation of the final arrangements for TOPS classification may be found here.
Locomotives
The first attempt to apply TOPS differed from the later approach in two significant ways:- xx/0 was not a valid sub-class number. When the second arrangement was applied original subclasses xx/1 became xx/0, xx/2 became xx/1 and so on.
- Some detail differences within classes were considered sufficient for a different class number to be allocated, rather than indicate it with a sub-class. In addition, there are a number of cases where conversions led to complete reclassification, where similar circumstances later would be indicated simply by allocating a new subclass. The change in approach led to some odd gaps in the list of locomotive classes when they were re-arranged as the principal class numbers were retained unaltered. Classes affected by this change in approach include:
- * Class 29
- * Class 31
- * Class 34
- * Class 43
- * Class 48
- * Class 72
Diesel Multiple Units
100-131: Driving Motor cars
140-150: Driving Trailer cars
160-190: Trailer cars
201-203: DEMU Driving Motor cars
211-212: DEMU Driving Trailer cars
221-225: DEMU Trailer cars
251: Express DEMU Driving Motor cars
261: Express DEMU Trailer cars
However, this arrangement was later revised so that each unit adopted the class number previously given just to the main type of Driving Motor car. The table below cross-references the old and new TOPS classes:
| First TOPS | Second TOPS | First TOPS | Second TOPS | First TOPS | Second TOPS | First TOPS | Second TOPS | |||
| 102 | 101 | 106 | 105 | 140 | 104 | 141 | 105 | |||
| 142 | 108 | 143 | 100 | 144 | 101 | 145 | 103 | |||
| 146 | 109 | 147 | 111 | 148 | 114 | 149 | 121 | |||
| 150 | 122 | 160 | 104 | 161 | 107 & 108 | 162 | 101 | |||
| 163 | 110 | 164 | 101 | 165 | 111 | 166 | 104 | |||
| 167 | 108 | 168 | 101 & 111 | 169 | 104 | 170 | 105 | |||
| 171 | 101 | 172 | 116 | 173 | 115 | 174 | 118 | |||
| 175 | 116 | 176 | 117 | 177 | 115 | 178 | 119 | |||
| 179 | 120 | 180 | 124 | 181 | 124 | 182 | 123 | |||
| 183 | 123 | 184 | 123 | 185 | 125 | 186 | 127 | |||
| 187 | 126 | 188 | 126 | 189 | 126 | 190 | 130 | |||
| 201/1 | 201 | 201/2 | 202 | 201/3 | 203 | 202/1 | 206 | |||
| 202/2 | 207 | 202/3 | 205 | 203 | 204 | 211/1 | 206 | |||
| 211/2 | 207 | 211/3 | 205 | 212 | 204 | 221/1 | 201 | |||
| 221/2 | 202 | 221/3 | 203 | 222/1 | 206 | 222/2 | 205 | |||
| 223/1 | 201 | 223/2 | 202 | 223/3 | 203 | 224 | 207 | |||
| 225 | 203 | 261 | 251 | - | - | - | - | - | - |
Electric Multiple Units
The first attempt to apply TOPS to the Southern Region's fleet of electric multiple units, saw classes being allocated according to the following division:40x: Southern Railway designed units
41x: 1951-type British Railways designed units
42x: 1957-type British Railways designed units
43x: 1963-type British Railways designed units
44x: 1967-type British Railways designed units
45x: Underground units
46x: 1971-type British Railways designed units
In comparison with the later re-arrangement, it is worth noting that types that were different were given the same class and identified only by sub-class, while those that were later treated as variations of the same class, were separated according to their construction period. When the new arrangement was applied, 40x classes were left untouched, but the others were changed as follows: