Rather than hijack the other thread I started asking about Mt. Rainier's depot, I figured I would start another one for this. I have one SP cab forward on my model railroad roster and would like to know a little more about where it could have run. I know the engines were designed for the tunnels and snow sheds up on Donner pass. I have also seen video of them running up and over Tehachapi pass. Did they run anywhere else on the SP system. I have heard reports of them running through the Cascades, which made me think a Washington state depot would make a good backdrop for such an engine. Did they actually run this far North or is my information bad (which is quite possible). Also, are there any good resources out there on this engines for some of us younger members that don't have access to some of the better books?

Thanks

While "Cascade Tunnel" is probably what comes to mind for a railfan, the Cascade Mountain range extends all the way from British Columbia to California.

I'm guessing the "Cascades" reference was in relation to the SP lines in Oregon, where I'm pretty sure they did run, rather than Washington state, which, as far as I know, rarely if ever saw any cab forwards. (I could be mistaken though...)

I think for modeling an AC in Oregon a location on the line from Eugene to Klamath Falls would be more appropriate. SP didn't really get into Washington.

According to Harlan's book ("Those Amazing Cab Forwards") they ran from Eugene to Klamath Falls to Roseville, and also on the Modoc line as well as over Donner Summit. However, the ICC banned them from the Siskiyou Line because of steep grades -- having the crown sheet in front made them vulnerable to low water (which caused 4017 to blow up in 1930).

Cab-forwards made it as far south as Los Angeles, and I have a vague recollection of seeing one on the SP LA to Yuma line west of Colton.

may explain the electrification like N&W and VGN

Dear Mr. Stangenberger

Could you tell me where the ICC had such authority? For the record cab forwards worked the pacific lines out of El Paso and the new locomotives were usually received in El Paso and set up for service to avoid Calif. Taxes on new locomotives. They were also worked on the western line divisions out of El Paso.

Robby Peartree

I have seen a photo of an AC class engine on the line from Westwood to Fernley.

Most likely, the ICC investigation found the locomotive's design made low water on descending grades an issue, and as a result the SP added a rule to their rule book. You could review the ICC accident report to see if they made any recommendations, and to be through you would need to review the design if other SP locomotives to see what the effect of grade on crown sheet water lever to see if other to grade.

If so, because the suggestion began with the ICC they are credited with the ban...

Randy

Please forgive my ignorance in advance, but wouldn't it be more of a problem on Ascending grades? I'm thinking why Shays are always pointed UP the mountain. Of course Shays almost always back down the mountain, where as these locomotives would continue down the other side and experience the ascending and descending grades.

Mike Stillwell
Buena Vista, VA.

Problem would originate upon coming down the hill...the glass would be reading higher than true/actual water level...leading to the inadequate amount over the crownsheet upon leveling or ascending the next incline. If the glass were showing adequate water on ascending the hill, there would be more than adequate water in the boiler

That's how I would read the problem.

BTW numerous B/W negatives of cab forwards in El Paso and New Mexico have been showing up on eBay over the last year.

sc 'doc' lewis

Operating "in reverse" with the crown sheet leading gives an inordinate incentive to the train crew to take risks with the water level. When pulling hard with a cab forward there would be extra incentive to operate with low water over the crown sheet, as the true volume of water in the boiler would still be high and thus a drag on steam production.

A standard locomotive operating with the crown sheet trailing allows the boiler to have good coverage with a lower true volume of water, allowing better performance.

The response at grade summit is also more challenging for a cab forward (although I guess oil firing allows better response). A cab forward reaches summit with little or no spare room to add water, as the boiler tilts and the water rushes towards the backhead. On a traditional engine, you reach the summit with the boiler really hot, and then close the throttle and suddenly need to cool the boiler down. Conveniently, you also need to add water to cover the crown sheet that is being exposed. So, you put on the injectors after reaching the summit to keep the safeties from lifting and have plenty of room to add water.

The Strasburg has a similar operational challenge outbound on departure from the station. The engine is leading with the crown sheet, and a lot of water must be carried for the pull, and then there is little flexibility to add water during the long drift down through the Grove. Water level management was always most stressful for me during this outbound segment.

Thanks Doc and Steve. I wasn't thinking of steam efficiency.

Mike Stillwell
Buena Vista, VA.