Santa Fe S-2 and S-4 Alco Switchers. Designed for use with the Santa Fe Alco S-2 and S-4 switchers, this exhaust stack provides thin walls (just .02" thick!), plus all of the correct angles and dimensions of the prototype. This exhaust stack was installed on many of the Santa Fe's Alco switcher fleet to deflect smoke from the engine over the cab, thus improving visibility. HO Scale (1:87.1). Includes 16 pieces.