I'm looking forward to both of these engines. I imagine that the GE switcher could accurately be used on any U.S. route, but what about the Cab Forward? Is it's use only accurate on Donner Pass? What about BtoSB? (Please excuse my ignorance of RR history.)
AHA! In good academic tradition, I just found the answer to my own question at
http://en.wikipedia.org/wiki/Cab_forward .
"USA: Southern Pacific
"... the best known example of the cab-forward design in the United States, the Southern Pacific Cab-Forward (also known to a lesser extent as "Cab-in-fronts" and "Cab-aheads") placed the cab at the front by the simple expedient of turning the entire locomotive, minus the tender, by 180 degrees, an arrangement made possible by burning fuel oil instead of coal.
"The cab forward design was widely used by the Southern Pacific Railroad, which developed it to deal with the peculiar problems of its routes. The 39 long tunnels and nearly 40 miles (64 km) of snow sheds of the Sierra Nevada Mountains could funnel dangerous exhaust fumes back into the crew compartment of a conventional locomotive. After a number of crews nearly asphyxiated, someone had the idea of running his locomotive in reverse. This meant that the tender was leading the train, which introduced new problems. The tender blocked the view ahead and put crewmen on the wrong sides of the cab for seeing signals. The tenders were not designed to be pushed at the lead of the train, which limited speeds. Southern Pacific commissioned Baldwin Locomotive Works to build a prototype cab-forward locomotive, then ordered more before the prototype had even arrived.
"All of the cab-forwards were oil-burning locomotives, which meant there was little trouble involved putting the tender at what would normally be the front of the locomotive. The oil and water tanks were pressurized so that both would flow normally even on uphill grades. Visibility from the cab was superb, such that one crewman could easily survey both sides of the track. There were concerns about what would happen to the crew in the event of a collision, and at least one fatal accident occurred on the Modoc Line when a moving locomotive struck a flat car. Turning the normal locomotive arrangement around also placed the crew well ahead of the exhaust fumes, insulating them from that hazard. One problematic aspect of the design, however, was the routing of the oil lines; because the firebox was located ahead of the driving wheels (instead of behind them, the usual practice), oil leaks could cause the wheels to slip. A nuisance under most conditions, it resulted in at least one fatal accident. This occurred in 1941 when a cab-forward with leaking steam and oil lines entered the tunnel at Santa Susana Pass near Los Angeles. The tunnel was on a grade, and as the slow-moving train ascended the tunnel, oil on the rails caused the wheels to slip and spin. The train slipped backwards and a coupler knuckle broke, separating the air line, causing an emergency brake application and stalling the train in a tunnel that was rapidly filling with exhaust fumes and steam. The oil dripping on the rails and ties then ignited beneath the engine cab, killing the crew.[1]
"No other North American railroad ordered cab-forward locomotives, although some, like the Western Pacific, did consider the type. Built to deal with difficult terrain, these remarkable locomotives became an easily recognizable symbol of the Southern Pacific. One example of the type, Southern Pacific 4294, is kept at the California State Railroad Museum in Sacramento, California. It is a 4-8-8-2 locomotive and is the only one to escape being scrapped.
"The North Pacific Coast Railroad, later part of the SP owned Northwestern Pacific company, rebuilt an 1875 4-4-0 into the first cab-forward locomotive. This innovative engine was built by William (Bill) Thomas, the NPC master mechanic who was nationally known and holder of a number of patents. Thomas used the running gear and frame from NPC locomotive 5, the "Bodega", which had been wrecked in 1897, to build NPC 21. With the addition a new and unusual marine boiler and an all-steel cab, installed in reverse order from standard engines, this unique creation earned Thomas a patent on the locomotive design. The 21 entered service in 1900, but only lasted a few years due to design flaws in the boiler. The crews were not happy with the new engine, finding it difficult to operate and scared of being on the front of the engine. They dubbed it "The Freak"."
Thanks to Wikipedia!