Network Rail KSW Sectional Appendix - SO250 Pantograph on the move
Class 378 drivers are authorised to change over traction modes using the following,

Maintain 25mph to signal VC818 and until change complete.


Reaching dual voltage zone warning board,
- reduce throttle to 0 or brake as required.
- pantograph down and then contact shoes down.

Wait till power change complete message and continue driving.

If signal VC818 is at danger. Stop at signal until proceed aspect then accelerate to 25 mph and complete above procedure.

Note. It might take up to 15 seconds for power change.