| 1 - 99 | Main aspect signals on the Main Lines. Evens on the down, odds on the up. |
| 1xx | Main aspect signals on the Badminton and Kemble Lines. Evens on the down, odds on the up. (Except SN125 & SN125R at Box) |
| 20x | Position light signals at Thingley Jn. |
| 21x | Position light signals at Highworth. |
| 22x | Position light signals at Highworth and Swindon West. |
| 23x | Position light signals at Swindon Down Goods and Swindon West. |
| 24x | Position light signals at Swindon East. |
| 25x | Position light signals at Swindon East. |
| 26x | Position light signals at Swindon Down Goods and Swindon West. |
| 27x | Position light signals at Wootton Bassett Stone Terminal. |
| 28x | Position light signals at Thingley Jn and Wootton Bassett. |
| 29x | Position light signals at Kemble. |
| 30x | Reversible crossovers at Uffington and Bourton. |
| 31x | Points at South Marston Euroterminal. |
| 32x | Points at Highworth Junction and Loop. |
| 33x - 34x | Points at Swindon East. |
| 35x - 36x | Points at Swindon West / Swindon Jn. (368 at Loco Yard) |
| 37x | (Former points at Rodbourne GFs, etc?) |
| 38x | Points at Rushey Platt. |
| 40x | Points at Wootton Bassett East |
| 41x | Reversible crossovers at Wootton Bassett (Main Line). (Except 419 at Chippenham) |
| 42x | Reversible crossover at Chippenham and Thingley Junction poitns. |
| 44x | Points at Kemble. |
| 45x | Reversible crossovers at Wootton Bassett West. |
| 46x | Points at Hullavington. |
| 6xx | Reversible Main aspect signals on the Main Lines. Evens on the down, odds on the up. Reversible signals are gernerally number 600 higher than the main line equivalent. |
| 7xx | Reversible Main aspect signals on the Badminton Lines. Evens on the down, odds on the up. Reversible signals are gernerally number 600 higher than the main line equivalent.
|
| 89x | Main aspect signals at South Marston Euroterminal. |
| DBxx | Main aspect signals on the Down Badminton. |
| DMxx | Main aspect signals on the Down Main. |
| MXx | Minety Crossing Signals. |
| UBxx | Main aspect signals on the Up Badminton. |
| UMxx | Main aspect signals on the Up Main. |