What are the filler caps for on the running board of a Jubilee Class?
Railway modellers love details, but sometimes a prototype's details can leave us scratching our heads and wondering why various bits and bobs exist and what they are used for.
If you have ever wondered what the filler caps are for on the running board of a Jubilee Class, they are used to replenish its sandboxes. Sand is used between the wheels of a locomotive and the track to give it traction in slippery conditions. The sand is stored in a special sandbox and released by the locomotive's crew when needed. Every now and then the boxes will require topping up using the (in this case) easy to access filler caps.