What keeps today's freight railroads from using modern, high-tech steam locomotives?

摘要

A "Modern" steam locomotives - the Norfolk & Western 4-8-4 Class J No. 611, Santa Fe 4-8-4 No. 2926, and Chesapeake & Ohio 4-8-4 Greenbrier No. 614 as extant examples - are truly amazing in the genius of their mechanical design. They are powerful and reliable. However, if you've ever been around the maintenance activities on them - monthly boiler washes, annual inspections, or even the daily lubrication, fire-cleaning, and servicing - you would quickly realize how labor-intensive these locomotives are, much more so than today's diesel-electric locomotives. They also require more logistics and labor in fueling and watering, and they are far less efficient in converting fuel into drawbar horsepower. Finally, the drawbar is where one of the biggest distinctions comes into play. A modern high-adhesion A.C.-traction diesel locomotive can simply out-pull any steam locomotive (including a 4-8-8-4 Big Boy). And diesel-electrics have dynamic brakes, which have become fundamental in modern train handling. That's important because much of today's traffic mix is high-tonnage if not high-speed. The latter is what steam locomotives are better suited for, and they worked well in the day when time freights - as opposed to tonnage freights - predominated. - Walter Rosenberger, Norfolk Southern Operations Manager Research & Tests.