This page describes the simple process of swapping a loco at a terminus station (such as at Buxton in this plan), allowing the first loco to be rested and changed for a fresh engine.  

 

Step 1 - The train approaches the platform with the blue loco, slowing to a stop

Step 2 - The train stops at the platform, with room at either end for the blue loco to get past the coaches 

Step 3 - The blue loco runs past the train on the lower loop, back onto the mainline

Step 4 - The blue loco runs into the depot sidings (via the headshunt) for refuelling

Step 5 - The green loco runs from the depot sidings, via the headshunt and mainline, onto the front of the train which is now ready to depart