Richard

It was probably designed for a Romford motor and 40:1 gears! However, things have moved on a bit since then and you can fit in pretty much whatever you like. Mine has a Mashima with a HighLevel 108:1 gearbox.

Hope this helps

Best wishes

Eric    

My  E1  also  has  missing  instructions  however  I  also  have  an  E1R  (a  modification  of  the  same  thing)  this  calls  for  a  DS10  motor  for  which  the  chassis  etch includes  a  mount.  No  gear  set  specified. 

Pete

Here's the finished article (well, running chassis) - still the brake gear and sand pipes etc to add - http://www.rmweb.co.uk/community/uploads/gallery/album_1858/gallery_12271_1858_682536.jpg