| style="color:yellow; background:#0B4559; border-bottom:3px solid" colspan="3" align="center"|BR Class 30 and 31 |
| tyle="color:white; background:#0B4559"|TOPS numbers | colspan="2"|(see left) |
| tyle="color:white; background:#0B4559"|Early numbers | colspan="2"|D5500D5699, D5800D5862 |
| tyle="color:white; background:#0B4559"|Builder | colspan="2"|Brush Traction |
| tyle="color:white; background:#0B4559"|Introduced | colspan="2"|19571962 |
| tyle="color:white; background:#0B4559"|Wheel Arrangement | colspan="2"|A1A-A1A |
| tyle="color:white; background:#0B4559"|Weight | 106.7111 t | tonnes |
| tyle="color:white; background:#0B4559"|Height | ft in | m |
| tyle="color:white; background:#0B4559"|Width | ft in | 2.67 m |
| tyle="color:white; background:#0B4559"|Length | ft in | 17.30 m |
| tyle="color:white; background:#0B4559"|Wheel Dia. | ft in | 1092/1003 mm |
| tyle="color:white; background:#0B4559"|Wheel Base | ft | m |
| tyle="color:white; background:#0B4559"|Minimum radius | chains | m |
| tyle="color:white; background:#0B4559"|Maximum speed | 90 mph | km/h |
| tyle="color:white; background:#0B4559"|Engine | colspan="2"|English Electric 12SVT |
| tyle="color:white; background:#0B4559"|Engine output | 1,470 hp | 1,100 kW |
| tyle="color:white; background:#0B4559"|Max. Tractive Effort | 35,900 lbf | 160 kN |
| tyle="color:white; background:#0B4559"|Power at Rail | 1,170 hp | 872 kW |
| tyle="color:white; background:#0B4559"|Brake type | colspan="2"|Air & vacuum |
| tyle="color:white; background:#0B4559"|Brake force | 49 tons force | kN |
| tyle="color:white; background:#0B4559"|Route availability | colspan="2"|5 (31/1, 31/6)
6 (31/4, 31/5) |
| tyle="color:white; background:#0B4559"|Fuel Tank | imperial gallons | 2,409 litres |
| tyle="color:white; background:#0B4559"|Heating type | colspan="2"|None (31/1)
Electric (31/4, 31/5, 31/6) |
| tyle="color:white; background:#0B4559"|Multiple working | colspan="2"|Blue Star |
EWS = English, Welsh and Scottish Railway