By the end of the the 20th century the Baldwin Locomotive Works was working hard at developing advanced ideas in steam power including compound engines but they were also looking further ahead. They had the foresight to partner with Westinghouse "developing electric motors for railroad work" in 1895. This is a 3 foot gauge locomotive built in 1904. It carries builders plates of both Baldwin and Westinghouse.
I'm not familiar with the Whitehall Railway but a bit of Googling led to this picture on the Collectors of White hall Pottery site. Could it be the same railway?