Complex sentence: Circus calliopes were sometimes installed in steam-drive carousels, or supplied with steam from a traction engine, which may also supply electric power for lighting and tow the calliope in the circus parade, in which it traditionally came last.
Split into simpler sentences: Circus calliopes were sometimes installed in steam-drive carousels, or supplied with steam from a traction engine. The traction engine could also supply electric power for lighting, and tow the calliope in the circus parade, where it traditionally came last.