Carriage is the entire train car, not just the interior, so that's not the right word. Compartment and cabin would both work. The difference between the two words is that a cabin is meant for people, while a compartment could be for people, or for other things like baggage.
A buffer stop, bumper, bumping post, bumper block or stopblock (US), is a device to prevent railway vehicles from going past the end of a physical section of track.
Press the green start switch. The switch must be held down until each cylinder begins to fire. The loco pilot observes the oil pressure, air pressure, and brake pipe pressure as they rise up after the prime mover starts running. They must keep a close watch on the battery charging process.
'Train' comes from a French verb that meant to draw; drag. It originally referred to the part of a gown that trailed behind the wearer. The word train has been part of English since the 14th century—since its Middle English days.
A locomotive frame is the structure that forms the backbone of the railway locomotive, giving it strength and supporting the superstructure elements such as a cab, boiler or bodywork.