My favorite locomotive is the Southern Pacific Cab Forward. These massive engines were the workhorses on the SP until they were retired in 1956. Cab Forwards were designed to make it easier for the crew to breath in the 40 miles of snowsheds and 39 tunnels on the Donner Summit route. By running the engine backwards with the cab in front and the smokestack in back, the crew got to breathe fresh air. The tender could be moved to the far end of the boiler from the firebox because the locomotives burned oil, which could be easily pumped forward. Cab Forwards are often called Mallets, but this is a misnomer except for the first models. A Mallet is a type of compound articulated engine where the steam exhaust of the first engine is fed into the second engine which has large, low-pressure cylinders. (They were designed by the Swiss engineer Anatole Mallet, and his name is pronounced Mallay.) Starting with the AC-4 class (4100 and above), SP changed over to simple 4-8-8-2 articulateds where both engines are fed steam directly from the boiler. These locomotives use more steam but are more powerful. The Cab Forward was a very powerful 6000 HP locomotive (an SD70MAC diesel is rated 4000 HP) capable of hauling long freight drags and, with 63 inch drivers, they were fast enough to haul passenger trains. An iconic SP train is a reefer block of perishable California fruit being rushed to Eastern markets over Donner Pass by Cab Forwards.
As much as I liked Cab Forwards I didnít own one until recently. The only models available were brass. I have always felt brass is more for collectors and not for running on a layout. The brass models need large radius curves and if they fall to the floor, they can represent a substantial loss! So when Broadway Limited came out with nice plastic AC-4 Cab Forwards with gorgeous sound I was hooked. I looked at one at the hobby shop and after running it back and forth on their test track, out came the my plastic. When I got home I found it didnít fit very well on shelf switching layout. Thus began the campaign to find a way to run Cab Forwards over my own Donner Summit. Before I brought this engine home, I had a nice sensible layout given the space constraint of one wall of a bedroom. It was designed for switching and I intended to run small diesels and steam on it. Broadway Limited's AC-4 is miraculously engineered to go around 22 inch radius curves but it does so with a huge overhang. Also it needs a long train behind it to look right.
I built a track along the back of the switching layout (which is now Sausalito/Mill Valley on the layout plan) and extended it over the headboard of our bed, looped it through our closet into the next bedroom and built a terminus in the 3rd bedroom with a big turntable to turn my AC-4 around. Now I can run my reefer blocks over Donner Pass and across the desert to Ogden, where the Union Pacific takes over. You can see and hear my AC-4 steaming along in the video section.
It is really cool to have my vision realized and to watch Cab Forwards pulling long trains over the summit. I am planning to completely redo the Sausalito area and build a second engine terminal and yard at the Western end. The switching layout was an interesting experiment. In the end, though, the lure of hauling freight over mountain passes proved irresistible.