Mexican State Railway class QR-1

The last steam locomotives built in North America had actually been ordered by the NdeM of Mexico. 16 each came from ALCO-Schenectady and Baldwin in 1946. Although they were of the 4-8-4 wheel arrangement, they were intended for freight service. The combination of four driving axles and two four-wheeled trucks ensured much power, enough flexibility for winding lines and an axle load that was not very high. As such, they were among the lightest North American 4-8-4 locomotives. Like the New York Central, the NdeM called them “Niagaras”. The last ones were already retired in 1965 after only 19 years of service.