Alright so, First attempt at scratchbuilding, and so far I have only gotten to a rolling chassis sitting on incorrect bogies. But heres how I made the NER Electric Luggage van so far.
I started out by printing out to the correct scale the design drawings, then transfering the correct dimensions to sheets of card.
This then allowed me to sort out all the dimensions before transferring this to plasticard to make a rolling chassis
I have not progressed further than this yet but I will update when I do