The Manila Railroad Company (MRR) announced the
dieselization of its locomotive fleet in 1954.
GE Transportation was selected as the supplier of diesel-electric locomotives. The agency bought fifty units in which thirty were
streamlined mainline locomotives and twenty were
switchers. Twenty of these were the UM12C
road switcher model MRR 2000 class. These were some of the first locomotives to feature the
cowl unit design. The locomotives were introduced to the MRR in 1956. Along with the
cab unit 1000 class, they formed the mainline locomotive fleet in Luzon until the late 1970s and the early 1980s. Starting in 1973, a newer
GE Universal Series type numbered the
PNR 900 class was introduced on mainline passenger services. Due to its popularity on services such as the
Amianan Express and the
Bicol Express, it eventually replaced the 1000 and 2000 classes from passenger service. The 2000 class continued service until January 1999 and the remaining units were immediately scrapped. ==State Railway of Thailand==