SP Cab Forwards - an idea not that widely used[?]

[Kozzie]

QUOTE: Originally posted by tebo41

This entire discussion has been very interesting. I happen to have a book, "Cab Forward," by Robert J. Church, DDS, self-published, printed by Central Valley Railroad Publications, copyright 1982, with no dabframmit ISBN, that seems to tell the entire story of the cab forwards very authoritatively. Dr. Church even mentions the odd-pot 4-4-0. This exercise proves to me that no matter how much you know about anything, there is always more to be learned. Thanks to all who contributed, I enjoyed reading it. CWT

tebo41 - thanks for those comments. [;)][:)]
I'm glad this post has been interesting for others as well as answering one of those questions that I have wondered about. [;)] [:)]

Dave

[Anonymous]

This entire discussion has been very interesting. I happen to have a book, "Cab Forward," by Robert J. Church, DDS, self-published, printed by Central Valley Railroad Publications, copyright 1982, with no dabframmit ISBN, that seems to tell the entire story of the cab forwards very authoritatively. Dr. Church even mentions the odd-pot 4-4-0. This exercise proves to me that no matter how much you know about anything, there is always more to be learned. Thanks to all who contributed, I enjoyed reading it. CWT

[Philcal]

Subject has been pretty well covered,the SP cab forwards were unique to the SP,and were used in passenger service.Have at least one photo of a cab-forward powering the "Owl",SP's San Francisco-Los Angeles night time train.Probably no where near as speedy as the GS-4s,the cab-forwards could produce respectable speed,and were truly dual service locomotives.

[Anonymous]

SP sure spent a lot of money on their locomotives working with environmental conditions rather than fix the problem. Why didn't they vent the tunnels? Would that not have been cheaper? Seems also that they continued building "specialised" locomotives for tunnel operations- the so called "tunnel motors" -right up to when UP merged with them. Did UP "fix" the tunnels- or just give up on using them?

Erik

[jchnhtfd]

QUOTE: Originally posted by Modelcar

...Jamie, understand what you are saying....If it was that critical for the water situation I wonder how they kept from blowing up many of them because we all know things don't always go as planned on daily routines...
I saw a large steam engine that had a boller explosion many years ago and it was total devistation....Nothing but the equipment below the frame was all that survived.

you'd be surprised how many steam engines did blow up[xx(]. While hardly a daily occurence, it was not exactly unheard of. Usually something silly like a water gauge not functioning right -- and there were lots of reasons why they didn't. Sometimes the injectors or feed water pump would pack it in, too. There was (and is!) astonishingly little margin between everything being just wonderful, and too little water and boom[:D]. The fireman had a lot more to do than just heave coal into the engine; he was a very important guy -- he watched the water!
Thing is, the cab forwards had a good bit less margin that the conventional arrangement, and so they did it more often...[:(]
But no steam engine is easy to operate correctly, and the penalty for error is pretty severe.
And you are right -- a steam engine which has had a boiler explosion doesn't have much left above the frame[:D]

[Modelcar]

...Jamie, understand what you are saying....If it was that critical for the water situation I wonder how they kept from blowing up many of them because we all know things don't always go as planned on daily routines...
I saw a large steam engine that had a boller explosion many years ago and it was total devistation....Nothing but the equipment below the frame was all that survived.

[jchnhtfd]

QUOTE: Originally posted by Modelcar

...In theory I suppose that could be a factor...but I'm sure the fireman had to keep the crown sheet covered above the firebox or the boiler wouldn't have stayed in assembled condition very long. Don't know what kind of compensation was made [if one was needed], to make sure all that area was water covered in an up hill attitude. I would think it would have been a critical factor but maybe the grades they operated on didn't make that much difference in keeping the water level above all the critical parts.

This was a real problem. Keeping the crown sheet covered with water on an upgrade -- even a relatively flat one (consider: your boiler is 60 feet long. On a 2 per cent grade the water level will be over a foot higher at the downhill end than at the uphill end. If you are steaming hard, the water level is down anyway... and if the crown sheet is the uphill end... [xx(]). There were a good few cab forwards which disassembled themselves because the water got too low; a considerably higher proportion of the fleet than for conventional engines.
Another slightly nasty problem was trouble with the oil feed on upgrades; again, you are using the most oil going uphill, and you have to pump the oil up from the tender. Quite a good ways. If the pump wasn't quite up to it, or the oil a little cold, or... you could lose your fire, albeit briefly. That wasn't the problem. The problem was when the durn thing relit, having gotten enough oil. Could be REAL scary[:0] -- as in BOOM!

[Anonymous]

These comments remind me of a few years back when someone asked Trains how the fuel was fed to these engines. Trains asked if anyone knew, which I thought was rather silly comming from the editors of TRAINS! Several of us joked about how many firemen it would take to carry scoops of coal to the firebox to keep the fire going. Oh, well.

[Anonymous]

CF's were used on almost all SP lines west of the Sierras. With the exception of the San Francisco commutes, CF's were used on the SF,SJ,&LA line until almost 1960. The CFs Were used extensivly for passenger service in the S.J. Valley and the Donner line. I never saw a CF adhere to a speed restriction except the ones placed due to general track restriction orders. If you check the records, a cab forward was never involved in a head-end collision that injured an engineer or fireman.

[vsmith]

QUOTE: Originally posted by M636C

Apart from Southern Pacific, I believe, in the USA only one short line ever built a cab forward, and it was a strange 4-4-0.

Yes, it was for the North Pacific Coast RR, a 36" narrow guage line that ran north from Saulsalito to Peteluma and up into the Pacific Coastline. It was oil fired and used a unique Marine type boiler. Heres a photo link:

http://narrowmind.railfan.net/440NPC21L.jpg

This was a 19th century engine and was way ahead of its time.

[Anonymous]

The genesis of the Cab Forward is a bit complicated but here's a quick rundown.
*The first two units, 4000 and 4001 were built as conventional 2-8-8-2s and then turned around with the cab in front. These were built in 1909 and classed as MC-1.
*The next fifteen were built as cab forwards and with the engineer on the left as the reversed first two were built. They were erected in 1909 and numbered 4002-4016 in class MC-2.
*MC-4 consisted of 12 more built in 1911 and numbered 4017-4028.
*MC-6 (there was no MC-3 or MC-5; the MC stood for Mallet Consolidation) were 20 more constructed 1912-1913. That ended the Mallet Consolidation program.
•MM-3 which stood for Mallet Mogul (2-6-6-2) comprised 12 units constructed in 1911 supposedly for passenger service. Their front trucks were totally unsatisfactory and were soon replaced with four wheel high speed trucks, making them into 4-6-6-2. These were the only Mallet Mogul cab forwards built.
In the twenties, all of the MCs and MM were rebuilt from mallet compounds to simple expansion locos, turning the MCs into ACs, but they never had their two wheel front trucks replaced and remained 2-8-8-2s, though the rebuilding saw the engineer's controls moved to the right side. The MMs were rebuilt into AMs and renumbered into the 3900s.
*Class AC-4 was constructed in 1928 with 10 "flat face" units.
*AC-5 was built in 1929 with 16 machines, and AC-6 saw 25 units in 1930. These numbered 4100 - 4150 and no more of this design were built.
*AC-7s were built in 1937 and had the new cab design on the 26 members of this class.
*From 1937 to 1944, AC-8 saw 28 units, AC-10 saw 40, AC-11 saw 30, and AC-12 saw 20. All had more or less the same cab design as the AC-7. See Kalmbach's wonderful "Guide to North American Steam Locomotives" for more.
*Of all the cab forwards built, only 4294 survives, and it may be visited at the California Railroad Museum in Sacramento, CA. All the rest were scrapped.
*Very few cab forwards were involved in collisions or mishaps. #4107 exploded on the Siskiyou Pass in 1929 when the water injector failed and the crown sheet was exposed. The engineer was killed and CFs never ran over the Siskiyou Pass again. This same engine in 1951 ran into some flatcars on the Modoc Line, kicking the first one up and into the cab, killing the crew. Also on the Modoc in June 1942, 4038 ran off the tracks and rolled on its side. The engineer survived but the fireman was killed. In 1951 on the Modoc, sabotage of the track put 4147 on its side in the ditch, but the crew walked away unharmed. All that happened in these wrecks would have likely been similar in a traditional back-cab locomotive. AC crews claimed their rides were cooler in the summer than sitting behind a backhead would produce.
*In the end, cab foward won because all the diesel locos today are built with their cabs on the front. It just takes a while for a good idea to catch on :-)

John Sipple, editor
Model Railroad News Magazine

[Anonymous]

> This class was used between El Paso and Tucumcarrie and burnt coal, not oil.

By necessity, a Cab Forward was an oil burner (no way to move the coal from the tender at the rear to the front of the engine easily. The only engines that weren't rear cab that burned coal were the camel back's, prodominantly used on eastern lines that burned anthracite (hard) coal. This was due to the massive size of firebox needed as hard coal burns much slower than soft (bituminous) coal. As for helpers pushing on the rear, many states had laws banning helpers behind the caboose (unless the caboose was unnoccupied-easily done by having the occupants ride in the cab of the helper). The roads that did couple after, however, required the caboose to have a steel underframe (irregardless of steel or wood body). If the caboose had a wood underframe, in order to prevent crushing it, it had to be dropped, and the helpers inserted between the last car and caboose.

[mike-65]

Cal State Rail Museum has one of these beasts - she's magnificent and massive.

Here's an interesting link, with a little more background info, and an 'odd' phrase:
"...the first California cab-forward..." apparently wasn't built by the SP...

http://www.csrmf.org/doc.asp?id=162

[broncoman]

Wasn't there an article about what UP's steam team went through, going through the snow sheds a couple of years ago when they brought both 3985 and 844 out. I was waiting in person at Soda Springs to watch them come by. Apparently the two SD70s that were helping dropped out forcing them to pu***he two loco's harder. It was amazaing how they looked by the time they made it to soda springs. I think one of the Steam team personel wrote the article, it was pretty cool.

[Kozzie]

Thnaks to everyone for all their comments. It has been very informative.

Apreciate it very much [:)][:)]

Dave

[Modelcar]

....Thanks Mark, for your comments....I've wondered about that situation for some time now having not seen any photos of the location since all that had happened and the line was rerouted. That must have been a tricky tunnel boring...Knowing their goal was to get to the water for it to drain...and not take the sand hogs with it.

[Anonymous]

Thistle "Lake" was drained by a tunnel specifically bored for that purpose at the same time the railroad tunnels were bored; otherwise, the water would have eventually overtopped the mudslide, caused it to fail, and obliterated most of the town of Spanish Fork at the canyon's mouth. There is no lake, but the new ground level is about four feet higher because so much silt washed into the lake while it was there.

[kenneo]

The comments about venting are correct. The snow sheds (and rock sheds, too) were vented out the top and also out the open sides. Mid-train helpers had a fairly well vented location. Helpers located in front of or close to a caboose usually had the rear-end crew in the locomotive.

Their ride took some getting used to. The cab was at the far end of a rigid frame balanced by the rear set of drivers. Take your school ruler, grab ahold of one end and notice how the free far end reacts to the inputs from your hand. Bouncy is about as kind as you will get, I think.

The cab-forwards were designed for and assigned to the Ogden-Roseville, Roseville-Eugene (Siskiyou (as far as Ashland) as well as the Natron Cutoff) and used extensivly also between Bakersfield and Taylor. The coal-burning AC's were used out of El Paso, generally towards the CRIP. Due to their large numbers they tended to wander about the system some, but were concentrated as described above.

You may also want to know, that just 10 years after the first cab-forwards were being introduced, SP and Baldwin designed a replacement for them for "flat-land" and mountain service that did not have the enclosure problems north and east of Roseville. These were the 2-10-2's (Prosperity Special) of which a large number were made and used, and the much slower 4-10-2's, which were the 5000 series 3-cylinder compounds.

[Modelcar]

...Concerning the massive flood at Thistle some years ago...and requiring the boring of a tunnel to support the revised routing through that area....Did the flood waters ever drain or has it become a permenant dam behind all the debris.....?

[GMS-AU]

Could it be said that any tank engine could be seen as a cab forward. Many British designs of tank engines had running lights on both ends and were used on branch lines or passenger service where they couldn't always be turned on a wye.

[Modelcar]

....It's my understanding they did have long tunnels to deal with besides the many miles of snow sheds....

[Anonymous]

Zach: That's right. Try the August 2001 issue, with the articles on helpers. It shows two GP40s (allowable by rule, see above) coupling up behind a lumber drag at Thistle, Utah -- now a ghost town buried in mud.

[UPTRAIN]

Hey, wasn't there a picture of a crew coupling onto the rear of a D&RGW train as a photo finish in TRAINS a few years ago? The locos were behind the caboose if I recall.

[Anonymous]

Some railroads did permit heavy steam power to push behind the caboose, though I wonder if anyone was foolish enough to actually ride in a wood caboose with a 2-8-8-2 hammering at the rear. In the diesel era, most railroads restricted the use of pushers behind cabooses, even though they were all-steel by that point -- D&RGW allowed two GP40s or one SD40T-2 or SD45 behind a caboose; anything more had to be cut in ahead of the caboose, or the excess units isolated.

I can't imagine that a cab-forward rode very well. Must have been pretty bouncy.

[UPTRAIN]

Espee thought it all up when they had to run those huge smoke belching locos through their long tunnels. No other railroad that I can think of embraced this design.

[M636C]

Since the problem was snowsheds rather than tunnels, spacing the pusher locomotives at the half way point or at the rear would allow the exhaust gases to disperse (through the open downhill side) enough to allow an acceptable (if not desirable) concentration of smoke in the air.

Photos I've seen suggest that ACs often ran just ahead of the caboose.

Peter

[Modelcar]

....From reading of the cab forward operations with SP over the years I did not realize the operation was so large to have had that many of these engines...The problem must have really been critical for them to change their operation like that with completely different design engines. Even with the CF units I suppose that limited a train to one engine on the front and then I wonder about the pusher operation.....ANY pusher would have been subjected to the gasses from the lead engine....?? What did they do...limit the length of trains to just one engine...? Were special instructions in force to keep all passenger car windows closed passing through all the sheds and tunnels...? When one really digs into this situation you wonder how the operation was sustained without really getting the company in trouble with asphyxiated passengers, etc....and at that time each freight train had...what, a crew of probably 4 or 5 men...plus more if an additional engine was included in the consist. Compare that to OSHA today...!

[Anonymous]

Before CF was the engineer going through 37 miles of snow sheds blind? If conventional 2-8-8-2s asphyxiated crews, how bad was it for crews of less powerful predecessors. Did passengers feel like they were in a chimney?

[kenneo]

FIRST --- These are NOT CF engines. They are Class AC-1 through AC-12 for the 4-8-8-2's and MC-1 through (at least) MC-6 for the 2-8-8-2's. That is, the 4-8-8-2's are. All but one class ran Cab Forward. This class was used between El Paso and Tucumcarrie and burnt coal, not oil.

AC = Articulated Consolidation, and were originally 2-8-8-2 cab to the rear, converted to cab-forward 2-8-8-2. The single axel lead truck did not track well (what was originally the trailing truck), and all 2 wheel lead trucks were replaced with 4 wheel.

AC's were passenger engines as well as freight and pulled all the passenger trains between Sacramento and Reno and, when not used as the "order engine", were helpers for passenger trains between Dunsmuir and Eugene. They pulled passenger trains elsewhere on the SP, as well. The SP had a fleet of 12 2-6-6-2's with 63" drivers that were designed especially for Sierra passenger service to end double-heading these trains. These engines were cab-forwards, also.

When I went to work for the SP, steam was not that far in the past, and I never heard any remarks about not liking riding up front. They did say, however, it was a bit of a strange feeling until you got used to it.

The originals, MC1's 4000 and 4001, built by Baldwin as conventional 2-8-8-2's. They hadn't made many runs out of Roseville before funerals were being held for the enginemen that were being asphyxiated. They were withdrawn from service, and sat rusting away on "flat land runs" for quite a while until Baldwin re-designed them with the oil and water feed lines moved to the front , the tender put there, and a "front put on the back" of the cab. Thus was born the cab-forward. Baldwin built 51 total Class-MC 2-8-8-2's (4000's) and 12 2-6-6-2's (4200's) (later converted, like their bigger brothers, with a 4 wheel lead truck) between about 1911and 1922. The first 10 AC's (4100's) (4-8-8-2) were built in 1928 (AC-1) and the 16 AC-2's were built in 1929, and 25 AC-3's in 1930. The conventional AC's were built in 1939 as 2-8-8-4's and were semi-streamlined, and built by Lima. Memory tells me the class was AC-9.

The SP had about 250 cab-forwards of various designs and classes.