No. 180 with some of the other N de M Double Fairlie Locomotives
Ferrocarril Mexicano (FCM) No. 180 was one of ten R-1 Class 0-6-6-0T steam locomotives built by the North British Locomotive Company in 1902 for the National Railways of Mexico (N de M).
No. 180 was a Double Fairlie type steam locomotive based on the designs by Robert Francis Fairlie. Essentially this places the cab over two fireboxes which feed two boilers, which in turn feed two sets of driving wheels which are placed on articulated trucks for maximum tractive effort. The engine didn't have a standard front and back as it was designed to be driven in both directions, eliminating the need for a turntable.
There were rectangular tanks on top of the boilers, which was the usual arrangement on oil-fired Fairlies. Heat from the boilers kept the oil warm and prevented it from becoming too viscous in cold weather since it was devoid of superheaters or modern valve arrangements.
The N de M primarily used Fairlies on a mountainous stretch of line between Mexico City and Veracruz. At least 49 of these enormous Fairlies were built, supplied, and imported from various locomotive companies situated in the United Kingdom between 1871-1911. They were built to standard gauge, weighing about 125 short tons (112 long tons; 113 t) apiece, and to this day are considered to be the most powerful Fairlie locomotives ever built.
No. 180 was used in service until it was eventually scrapped in 1924 when the line was electrified and due to the immense operating cost.