Glossary of North American Railway Terms - S

S

• Screamer or Screaming thunderbox: EMD F40PH locomotive, in reference to it operating in a constant state of full throttle (in order to provide head-end power to passenger cars). Coined by MBTA railfans.

• Sergeant Stripes: a Canadian National locomotive in the 1970s-1980s paint scheme featuring light grey stripes on the locomotive's long hood.

• Slug: A locomotive, with or without an operator's cab, which lacks a diesel engine, and draws power for its traction motors from a normal locomotive, known as a "mate" or "mother."

• Speeder: a small, motorized track inspection vehicle. Also called motorcar, trackcar, putt-putt, or golf cart.

• Stacks: Nickname for double-stack cars or trains.

• Stealth Unit: The early CSX grey & blue paint scheme. So named for their virtual invisibility in poor light. Also refers to NS D9-40CWs in light gray primer paint, and a scheme used on some Metro-North locomotives.