Cab Forward

The SP cab forwards seemed to have the best visibility to the front of any steamer.  If I am correct they were built that way to keep the engine crews from being gassed in mountain tunnels.  With these two things going for them, why did other railroads not use them? 

 

 

 

The TEXAS SPECIAL:  The REAL RED streak of the golden prairies!

Original Post

Yes - SP originally developed the cab forward concept to prevent engine crews from getting overcome by gasses in Sierra snow sheds and numerous tunnels and were employed throughout the entire SP system in California and the Southwest. Many other U.S. railroads however were reluctant to implement the cab forward idea due primarily to crew safety in the event of a head-on accident. And yes track visibility was excellent on cab forwards but engine crews weren't keen on the idea on being seriously injured or killed in an accident.

RJR posted:

Brandy, actually, folklore says it was.  Supposedly an engineer ran a conventional loco tender first to avoid the smoke, which would mean the cab was at the forward end of the loco.

I'll take more than "folklore," thank you very much. I've never seen this written about anywhere.

Steve

 

Dominic Mazoch posted:

The SP cab forewords seemed to have the best visibility to the front of any steamer.

Yes, in good weather.  I'm not so sure, though, that the visibility was great in a snowstorm.  There was a slanted glass which was supposed to divert at least some rain, but I would imagine that' when snow accumulated on the windshield glass, there was only one option - head out the window.  Perhaps the beackhead kept the cab warm enough to melt any snow that hit the glass, but I would not guarantee it.

Tom

 

Superintendent, High Plains Division (O Gauge) 

The Panhandle & Santa Fe Railway Co.

Lone Star Hi-Railers

Santa Fe, All the Way

This is from The American Society of Mechanical Engineers brochure, dated May 7, 1981, about the #4294 Cab-In-Front Articulated Locomotive:

"Many legends and secondhand stories abound regarding the solution of the problem. Several tests were made backing the locomotives with the tender running first. This proved to be unsatisfactory, so the daring decision was made to turn the locomotive around and run with the cab in front. The tender was trailed from the L.P. engine."

Besides, only the AC's (with the exception of the AC-9) were cab forwards. The rest of SP's steam fleet were conventional in design.

Hmmm . . . first class was an AM.  Then came the MM class - my personal favorite, and originally a 2-6-6-2, or Mallet Mogul.  Then came the AC and AM classes.

I have photos of most.  My collection lacks only the very early AC and AM classes.  I prefer the Mallet versions.

Number 90 posted:
Dominic Mazoch posted:

The SP cab forewords seemed to have the best visibility to the front of any steamer.

Yes, in good weather.  I'm not so sure, though, that the visibility was great in a snowstorm.  There was a slanted glass which was supposed to divert at least some rain, but I would imagine that' when snow accumulated on the windshield glass, there was only one option - head out the window.  Perhaps the beackhead kept the cab warm enough to melt any snow that hit the glass, but I would not guarantee it.

I don't believe the cab forwards were ever equipped with windshield wipers either.

Northern Pacific considered ordering cab forward 4-6-6-4's, based on their Z-6 design, for use through the Stampede tunnel.  They tested a Z-6 running in reverse, with a deflector over the smoke stack to protect the tunnel roof from the exhaust blast.  The tests showed that a Z-6 would make it through the tunnel, but it was with very tight clearances.  All they would need is a derailment in the tunnel to block the main.  So instead they just kept running old Z-3 compound 2-8-8-2's until diesels replaced them.

Stuart

 

The light at the end of the tunnel is the headlight of an on coming train!

smd4 posted:
RJR posted:

Brandy, actually, folklore says it was.  Supposedly an engineer ran a conventional loco tender first to avoid the smoke, which would mean the cab was at the forward end of the loco.

I'll take more than "folklore," thank you very much. I've never seen this written about anywhere.

Quoting from "Cab Forward" by Robert J. Church, page 21: "As an experiment, a trip was over The Hill with the tender leading. The exhaust gave the crew no problem, but the tender in that position was unsafe, so operation in this manner was not considered as a permanent solution."

smd4 posted:

Thanks Big Jim.

Sounds like all they were doing was running an engine in reverse. Does that mean the Texas was really the first cab forward?

That would be a stretch, but, Church did give reference to the one below. 

NPC

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A model of that NPCRR loco would look great on my layout.

FWIW, during the December 1947 blizzard, the DL&W lost its catenary.  To run commuter service, it used steam locos to pull the MU cars (which had no heat due to no power).  Lacking sufficient loco turning capacity at the west end of the route, the locos ran in reverse heading east.  Since these were coal-burners, not oil, while the crew didn't get smoked, they did get a dose of coal dust when running tender first.

Brandy posted:

I always wanted to see the 1st version that was coal hand fired..............An attempt at Humor..!

The Germans built a coal fired cab forward 4-6-4, 05-003.  It used pulverized coal which was piped to the fire box.  It also held the world speed record for steam locomotives until the A-4 class Mallard 4-6-2 won that title.

Stuart

 

The light at the end of the tunnel is the headlight of an on coming train!

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