During the summer I have been building my G gauge garden railway. My track is raised 24 inches off the ground. I have now acquired an “engine” shed that I want run my loco,s into at the end of the day. I need the benches in the shed to have a comfortable working hight, higher than 24 inches . What is considered to be the maximum or usable angle / slope for the track that I can use to give me a comfortable working hight for the Engine shed bench’s ?