from wiki:
The fuel used depended on what was economically available to the railway.
Until 1870, the majority of locomotives in the USA burnt wood but, as the Eastern forests were cleared, coal gradually became more important. Thereafter, coal became and remained the dominant fuel worldwide until the end of general use of steam locomotives.
In the USA, the ready availability of oil made it a popular steam locomotive fuel after 1900 for the southwestern railroads, particularly the Southern Pacific.
You can stack it any way you like. I've seen crazy tall wood stacks on tenders and I've seen Climax and Shays with so much wood piled on it didn't look like the crew would fit.
Something tells me Richie can dig up some pics
