Northern Pacific cab forwards

[IA and eastern]

Northern Pacific was looking to buy cab forwards for the Stampede tunnel. Would the Southern Pacific AC-12 4-8-8-2 cab forwards fit through the Stampede tunnel or would the Northern Pacific have gotten something smaller. Gary

[jrbernier]

  If the giant Z-5 class 2-8-8-4 'Yellowstones' would fit, I suspect the cab forwards would have a chance to get through the tunnels on Stampede.

Jim

[Penny Trains]

And with less mayhem perpetrated upon the crew in the cab to boot.

[Overmod]

Penny Trains

And with less mayhem perpetrated...

A subject about which you would know! 

[CSSHEGEWISCH]

The only proposal for cab forwards for a road other than SP with which I'm familiar was for WP 2-8-8-2's.  The proposal was turned down since engineers preferred having all that metal in front of them in the event of collisions.

[IA and eastern]

Northern Pacific was looking at 4-8-8-2 and 4-6-6-4 cab forward locomotives when they decided to transfer more W-3 and wait for EMD FT locomotives. Gary

[wjstix]

I seem to recall reading long ago about CP proposing a cab-forward to deal with their tunnels, perhaps a version their 2-10-4? I think sketches (if not not actual blueprints/designs) were made, but it never got farther than that.

[kgbw49]

Here is a drawing and article on a hypothetical CP 4-10-2 ”Connaught” cab-forward:

http://www.trainweb.org/oldtimetrains/CPR/steam_locomotives/connaught.htm

 

[Overmod]

kgbw49

Here is a drawing and article on a hypothetical CP 4-10-2 ”Connaught” cab-forward:

http://www.trainweb.org/oldtimetrains/CPR/steam_locomotives/connaught.htm

Fascinating to see what is, and isn't, thought important by someone 'brought up' in a particular railroad culture.

He wouldn't get far with a 4-10-2 that didn't equalize the leading truck with the drivers, at least the first group.  I'd presume the equalization was provided in the normal way, taken up the arms of the trailing truck to points on the frame inboard in line with the springing, and these (perhaps siamesed together) could easily be run inboard to a new point for the four-wheel operation, with pivot point adjusted for correct basic distribution.

The two-wheel 'pedestal' truck is largely a hangover (and I don't think CP used the Cartazzi arrangement, about the only thing that would give superior tracking to a Bissel running in its preferred direction.  While the geometry of the existing lead truck running 'in reverse' isn't as optimal as a normal Delta truck would be, it is still just fine as far as lateral control at that end of the engine needs to be... with one exception.

Normal "second edition" Deltas apply the steering correction as far to the rear and outboard of the chassis as possible, neither of which are observed with a 2-wheel Bissel; he'd be welding wings to outboard pockets with geared quadrants and eccentric-gear rockers to implement the progressive loading without spring surge that is desirable to keep the back of the locomotive stable.  He could also provide this with some care using a Franklin radial buffer variant that uses the tender to help control motion of the rear of the chassis -- the 'pushed-up' location of the forward tender truck should assist with this.

Meanwhile, note the care and attention he gives to the control changes, and to the plumbing and maintenance of the Elesco setup.

In light of NDG's earlier comments on the swivel-headlight feature, I thought some of the comments on how to light up the ditches were interesting.

[LOWRANZO STEVE PANZIK]

According to the book by Frey and Schrenk "Northern Pacific Supersteam Era"

page 161 & 162, the NP did test runs with the 5117 in 1937 through Stampede Tunnel in Washington State. Since the tunnel had a crest inside, the locomotive had to work both ways inside the tunnel. The cab temp was 49 degrees before entering the tunnel and went to 130 degrees within 90 seconds of entering. The clearances were tight. 

Also memtioned on page 163, the NP took a cue from the Espee and ran the 5117 in reverse through the tunnel to memic a Cab Forward which greatly reduced the temp in the cab. But the ideal for a Cab Forward never happened.