Re: Outside frame vs Inside frame

In the case of the East Broad Top, clearances were probably more of an issue than a drop pit. The two tunnels were a template of sorts for all of the EBT engines. The largest engines, 16,17, and 18, had short squat domes, and a short stack, plus cabs mounted lower than say a K-27, for the sake of comparison. Enlarging the tunnel bores was an expense the EBT didn't want, so the engines from the early days to the last used were of a minimum height to make it through the tunnels. An outside frame engine would be wider, so besides height, the tunnels would have to be widened.
Given the clearances, the EBT engines had enough tractive effort to do the jobs they were intended to do. The only time the EBT did any work in the tunnels was to acomodate standard gauge cars on narrow gauge trucks. Even then, photos exist showing the shop crew removing the top of a tank car dome to fit through the tunnel.

brian b