The SRS / CBS twin drum tensioning unit delivers contact and catenary wire at part operational tension.
| Weight: | 18 tonne |
| Maximum force at the bull wheels: | 7.2kN |
| Maximum Drum diameter: | 2m |
| Maximum weight of Drum: | 2,350kg (Tower end), 1,450kg (Cab end) |
| Maximum width (Cable Drum): | 1,100mm |
| Maximum reach (m): | 18.2m (height), 14.5m (lateral) |
| Travel under live OLE: | Yes |
| Maximum Cant (mm): | Working 160mm (travelling 150mm) |
| Adjacent to open line working: | Yes |