The A-3174 (LRS-1200) was a model of 1,200 hp (895 kW) B-B diesel locomotive built by Lima-Hamilton in 1950.
A second order of 17 was outstanding at the time of Lima-Hamilton's merger with the Baldwin Locomotive Works, but owing to insufficient time to build the locomotives before the locomotive production ceased at Lima, NYC agreed to receive RS-12s from BLH, they were built at Eddystone, PA. Lima-Hamilton never assigned a model number to their models, but instead referred to them by specification numbers.
Lima-Hamilton assigned A-3174 as the specification number for this particular model.
Most of these locomotives were retired in the mid-1960's, although two remained in service into the Penn Central era.
The surviving units, 8062 and 8063, were rebuilt to replace their original Lima prime movers with EMD V12 567C engines, like those in SW1200s and E8's.