Union Pacific Railroad's GE 4500 gas turbine electric locomotive...good idea, bad idea?

What does one "trade off"...efficency or safety? Well, "safety" won. It was a cool idea but way too dangerous.

In 1953, the first U.S. propane fueled gas-turbine locomotive was placed in service by the Union Pacific Railroad. It delivered more than 4,800 h.p. (more than three diesel units) and had the advantage of clean burning, which kept the turbine blades free from carbon deposits with less wear. Delivered in May 1953, UP 57 was a GE 4500 gas turbine electric locomotive (GTEL) equipped to burn propane. Road tests were run between Los Angeles and Las Vegas. However, the high volatility of propane required extra safety precautions for the pressurized tender, which seemed to offset the advantages. So, although the test was considered a success, the locomotive was converted back to burn residual fuel oil in Jan 1954.

Union Pacific GTELs