The GE U36B is a four-axle 3,600 hp (2.7 MW) B-B diesel-electric locomotive produced by General Electric from 1969 to 1974. It was primarily used by the Seaboard Coast Line Railroad and its successors, although thirteen provided the power for the original Auto Train. The U36B was the last GE high-horsepower universal series locomotive.

The U36B and the six-axle GE U36C were designed to operate with the MATE (Motors for Additional Tractive Effort) slug. The MATE had four traction motors, allowing power from the locomotive to be distributed over a total of eight traction motors for double tractive effort.

In railroading, a slug is a version of a diesel–electric locomotive which lacks a prime mover and often a cab. It derives the electrical power needed to operate its traction motors and motor controls from a fully-powered mother locomotive.

1. CSX MATE 5204 (built by GE as SCL Mate 3204 in August 1971) and U36B 5790 (ex-SCL 1840 built in February 1972) in Tampa, FL on January 22, 1988 MATE is an alternative name for certain slugs, see

2025年1月2日 · The U36B was the final four-axle variant General Electric cataloged as part of its Universal line. It was also the powerful B-B road-switcher any manufacturer ever offered, boasting an impressive 3,600 horsepower.

A pair of U36B/MATE slug sets heads for Tampa with phosphate loads at Edison. Date of photo approximate.

2013年2月27日 · For general instructions, I followed John Edwards’s excellent article on modeling SCL U36B and slug sets in the Aug 1988 issue of Model Railroader. Thank goodness I lived near San Diego at the time and was able to get my hands on this back issue via the SDMRM’s wonderful library!

Built as Seaboard Coast Line (SCL) 1835 January 1972 (c/n 38278), it was modified during construction to operate with MATE (Motors for Added Tractive Effort) slugs. When this locomotive was built, 900 horsepower per axle was a lot, and wheel slip technology had not yet caught up with that kind of power.

The SCL 3200-series MATEs were not intended to be yard slugs. They were bought for use on the Bone Valley phosphate trains and were quite successful in that role. In flat switching, the U36B/MATE combos were painfully slow to load up, and we always felt that a pair of RS3s would get the job done much quicker.