Bringing heavy trains safely down Donner Pass grades using Cab Forward

[bwfer]

Were Cab Forwards also used on passenger trains over Donner Pass or did SP put GS4's up front?

That's a big yes! Cab Forwards were standard power for such trains as the Overland Limited (Trains # 26 and 27) and the Gold Coast Commonly referred to as the "Cold Roast" between Roseville and Sparks. If the consists were unusually heavy, two ACs were double headed as SP operating rules prohibited pushers on Passenger trains.

GS4's were rarely used over Donner Pass probably because of their 80 inch drivers would tend to be somewhat slippery in addition to being hard on the rails due to the many curves and curvature, , however GS6s were occasionally used. Mountain (4-8-2s) and Consolidations (2-8-0s) saw frequent duty on the hill.

[_o_OOOO_oo-Kanawha]

Mountain (4-8-2s) and Consolidations (2-8-0s) saw frequent duty on the hill.

I've found using Google search that SP even ordered massive 4-10-2 "Overland" express freight locomotives first but later turned to the Cab Forward design.

Now we know what we want next for Southern Pacific motive power to go with the upgraded Donner Pass route.

[philmoberg]

... Now we know what we want next for Southern Pacific motive power to go with the upgraded Donner Pass route.

My friend, the late Bob McKernan, used to say, "Never open a can of worms unless you have a much bigger can ready to put them back into." Having spent most of his railroading career with the New Haven, he later worked for PC and finally Conrail before retiring, so he had a lot of experience with folks opening cans of worms ...

So ... while we're at it, I'll offer my two cents' worth. IMHO an Mt5 or Mt6 would be a natural. To my eyes, these were the best-proportioned steam power the SP had. A GS6 would be a nice addition, as well. All of these were dual service machines, and fill an important gap in the a steam-era roster. The 2-8-0 that came with the Challenger is a classic Harriman design, but probably needs a different tender. This would give you a basic roster to realistically handle all the classes of traffic on Donner in the Transition Era. The earlier ACs, with the flat cabs, would add nice variety, but these were all gone by '55, or thereabouts. I have a personal fondness of the Mk5s, but that's because I hail from the other end of SP territory, where some of them were actually built.

[_o_OOOO_oo-Kanawha]

Yes, Phil, Mountain types were generally considered the steam engines with the nicest proportions,esp with tall drivers like the NYC Mohawks.

Here is SP 4323 in passenger service :


Here is a pair in freight service led by SP 4345, snow plow, foldable exhaust splitter and all. These engines certainly saw service on Donner Pass I suppose:


SP 4347 is an example of a rebuilt engine that has been visually overhauled to match the streamlined Daylight service and its advance and connecting trains with that skyline casing:


We also could use some nice Mountains on the Horseshoe Curve, COARW, NSAND and probably B-sB as well. A basic late USRA heavy 4-8-2 with different tenders will do for a starter.

I would't say no to this heavyweight on my DP roster either, 3 cylinder 4-10-2 SP 5023. Now looking for a photo with her in DP service:

A later photo with the same engine rebuilt at the other end of the line, note the levers connecting the valve gear to the middle cylinder.

Here is a close up of the front with the connecting rod of the Gresley conjugated valve gear clearly visible, running across the middle cylinder front cover:


There is so much we could want that I sincerly hope the Cab Forward, upgraded Donner Pass and coming Sherman Hill will be commercially succesful and finaly give TS2012 a solid foothold in the US market. Even the ancient MSTS is given a new life in the guise or R8, so there must be a huge market ready for opening.

[bwfer]

The SP Overland class 3 cylinder 4-10-2s wre originally acquired for Donner Pass Service as they could out perform the compound Class MC cab forwards. . However due to their long driving wheelbase they caused increased rail wear on the curves even though being equipped with lateral driving boxes.

At the same SP started rebuilding MC1, MC2, and MC3 compound Cab forwards into simple AC1, Ac2, and AC3s. These new re-built single expansion Cab forwards out performed the 4-10-2s in addition to being alot easier on the track. The 4-10-2s were transfered other divisions.

[philmoberg]

... We also could use some nice Mountains on the Horseshoe Curve, COARW, NSAND and probably B-sB as well. A basic late USRA heavy 4-8-2 with different tenders will do for a starter.

I would't say no to this heavyweight on my DP roster either, 3 cylinder 4-10-2 SP 5023. ..s.

The SP Overland class 3 cylinder 4-10-2s wre originally acquired for Donner Pass Service as they could out perform the compound Class MC cab forwards. . However due to their long driving wheelbase they caused increased rail wear on the curves even though being equipped with lateral driving boxes. ...

Three-barrel 4-10-2s? I was aware of several different classes of three cylinder power in the U.S., but this is the first I've heard of these! It's a nicely-balanced design for a machine that big. I can see the point about the long wheelbase on a route like Donner Pass, though. The forward visibility must've been a real problem, as well.

I quite agree on the subject of the USRA Mountain types. Nearly every U.S. railroad of had some version of this design, and the number of copies and derivatives of it make for a very impressive history. IIRC everything below the boiler is common to both the light and heavy variations, so this would be a relatively economical project for any builder willing to undertake it.

[BR50Kab]

Yes, but is "pumping" the brakes safe practice with a 4000 ton train going down a long >2% grade using exhaustible air brakes of crude design?
I suppose those steam era box cars and reefers had single release triple valves only. So once the brakes were released, the car's reservoir had to be filled completely before the next brake application could be made. With a long train and leaks along the trainpipe that should take some time and all the while gravity pulls ....

Anyway, while releasing the brakes in this particular scenario the train quickly exceeds the speed limit and goes into emergency because the scenario aborts.
So I'd rather set this small amount of air on the cars and sort of "pull" the train down the grade.

Where Cab Forwards also used as pushers and did they stay on the train once it got over the top? There is that covered turntable near the summit for a purpose, though I haven't tried to turn a Cab Forward there yet. Were pushers connected to the train line and braked from the road engine? Or were they bailed off and relied on the engineer working the independent brake? Was it SP's practice to cut out the caboose and put it back behind the pusher? If the conductor needed to put the train into emergency by dumping the air, the caboose had to be connected to the trainline, and hence the pusher also.

Interestingly, you meet several opposing reefer blocks using just two GP9 pulling about the same amount of cars. I don't know yet wether open hatches denote empty cars.

This is an old thread so sorry for bumping this... i actually was looking for advice to keep my Cab Forward on speed uphill for some other mission when i saw this remark.

At first braking on early railroad systems was done by the locomotive itself until trains became to heavy for that. Then they started using maually brakes on individual cars by brakemen. After that they used pressure on a pressure line to apply the breaks... until the pressure failed and they found out that relying on pressure to be able to break is unsafe. So several inventors (Westinghouse, Knorr, Kunze-Knorr) came up with the other way around: if you need pressure to release the brakes it is much safer if for some reason the pressure fails.

Most systems use pressure reservoirs to be able to move cars uncoupled to a train (there are switches to use the reservoirs pressure instead of the main pressure line) for instance when shunting over a shunting hill in the yard where the cars roll by gravity force.

Although this system is far more secure incidents did happen where trains refused to break. Before WWII a German engineer on a BR 01 Pacific (BR or Baureihe is German for Class) at full speed noticed he could not break. As there was no safe way to reach the end of his engine to losen the pressure line he moved to the front over the small platform without girders meant to service the engine while standing still. He made it succesfully and also manged to release the pressure valve and stopping the train alyhough he was badly burned, probably by the steam coming out of the cylinders.

In the 70's or 80's a Dutch express train failed to stop in time, they set all the junctions right and kept her path free until after a very long way she came to a halt.

As for the Riggenbach brake system, this was applied to some of the German BR 94 tender engines, a medium speed five axled all axles coupled Prussian steamlocomotive. As far as i know this was pure adhesive traction (no extra gear wheel and special rail in the middle on the steeper parts although the slopes it managed were far less steep than with a gear wheel and a special rail). It was however used to reduce the weardown of it's brakeshoes and a special damping device (muffler?) had to be used to reduce the noise of the high pressure air released from the cylinders besides the cooling.

[arizonachris]

And what do you mean by cab forward?
Daniel

The Cab Forward design was created for the long tunnels that were on the Southern Pacific mountain's routes: http://en.wikipedia.org/wiki/Southern_Pacific_4294 Basically so the engine crews would not pass out or die from lack of air to breathe.

[buzz456]

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