Can be expanded with Railroad Club Car (set 10002-1), itself a re-issue of set 4547-1.
Can be motorized using the 4548-1: Transformer and Speed Regulator or similar parts from other sets.
"This set came with a choice of two modern styled locomotives, either of which could be constructed using the various pieces in the box. The model shown here contained a combined driver's cabin and dining car area separated by an engine space. The train ran on metal tracks and the set also contained a buildable railway platform and 11 minifigures. Originally from 1991, this model was one of the few sets to be relaunched with completely new packaging as part of the LEGO Legends series in 2001."
-- From employee gift re-creation (set 4002016-1-s4) building instructions.