The Power Box ^TM

The Power Box family of products has official approval from Network Rail and will be used extensively on the UK's railways.  The official letter is below, the text says:

Product Acceptance : Signalling 650V power supply switch & fuse box

I refer to your recent 'proposal for product acceptance" form in respect of the above.

Our engineering group responsible for such matters has confirmed that this equipment does not need formal product acceptance by Network Rail.