FEF-1
The first twenty locomotives, numbered 800-819, were delivered by Alco in 1937. The "800"s as a whole followed - like Northumbrian 108 years earlier - the simplest possible arrangement of only having two outside cylinders. Fitting Alco's lateral motion devices to the leading coupled wheels eased the negotiation of curves. Complicated accessories often spoilt the basic simplicity of so many US locomotives, but UP resisted most of them, resulting in an elegant, uncluttered appearance. Despite frequently moving at speeds over 100 mph (161 km/h), the forces and stresses on the coupling and connecting rods were kept within acceptable limits. There were thus excellent results, and there were many reports of reaching the design limit of 110 mph (177 km/h).
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