# Picky Intermountain Cab Forward



## Againtrains (Mar 6, 2016)

Ok I have found my Intermountain Cab Forward to be a little stubborn on some turn outs. Being it Atlas Custom Line, standard Atlas, or Peco. Because of the wheel base of the engine it would sometimes jerk through a turnout. I found by using a cutting disk in the frog fixed most problems. So now that I know, it is Classified My Test Engine, if it works then anything else I have will work. I did have one problem that drove me nuts for a while and first I blamed the Cab Forward. I was getting a dead short in one Peco turnout... Not every time... Then at one point the whole system just shut down and would not power up. That was after the Cab forward had passed though a newly laid turn out(minor track change). Come to fine out after discounting all track feeds, and replace one by one three different times. It was a spike that had been dropped between the points and the main rail...it would bounce and cause a dead short. SO COUNT YOUR SPIKES AND MAKE SURE YOU KNOW WHERE THEY ARE!!!:laugh:


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## Fire21 (Mar 9, 2014)

Againtrains said:


> It was a spike that had been dropped between the points and the main rail...it would bounce and cause a dead short. SO COUNT YOUR SPIKES AND MAKE SURE YOU KNOW WHERE THEY ARE!!!:laugh:


Adds another aspect to being a rivet counter! :laugh:


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## rrjim1 (Mar 12, 2015)

When did Broadway Limited make a Cab Forward in N-scale?


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## Againtrains (Mar 6, 2016)

*Opps....sorry*

I had Broadway Limited on the brain for some reason....all I have from them is the auto water tower that has sounds. The Cab Forward is Intermountain. Sorry about that....


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## traction fan (Oct 5, 2014)

*Cut frog?*



Againtrains said:


> Ok I have found my Intermountain Cab Forward to be a little stubborn on some turn outs. Being it Atlas Custom Line, standard Atlas, or Peco. Because of the wheel base of the engine it would sometimes jerk through a turnout. I found by using a cutting disk in the frog fixed most problems. So now that I know, it is Classified My Test Engine, if it works then anything else I have will work. I did have one problem that drove me nuts for a while and first I blamed the Cab Forward. I was getting a dead short in one Peco turnout... Not every time... Then at one point the whole system just shut down and would not power up. That was after the Cab forward had passed though a newly laid turn out(minor track change). Come to fine out after discounting all track feeds, and replace one by one three different times. It was a spike that had been dropped between the points and the main rail...it would bounce and cause a dead short. SO COUNT YOUR SPIKES AND MAKE SURE YOU KNOW WHERE THEY ARE!!!:laugh:


 Againtrains;

You say that "using a cutting disc in the frog fixed most problems." Did you cut the frog's flangeways wider, or deeper, or both? Did you check the wheels of the cab forward and the turnouts with an NMRA gage?
I'm glad you were able to fix your problems, I'm just curious about how.

Traction Fan:smilie_daumenpos:


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## Againtrains (Mar 6, 2016)

*Frogs*

I had to widen a few of them. It did not take much to fix the problem ones. Just a couple of swipes with a cutting disk. Running the Cab Forward slow you could see it start to catch then you would have the problem. The thing is this did not happen on all turnouts of the same brand. Yes the wheels have been checked with a gauge. The only other steam I have are a Atlas Shay and Bachman K4(sound) both of those never had problems.


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## traction fan (Oct 5, 2014)

*Long steam short steam?*



Againtrains said:


> I had to widen a few of them. It did not take much to fix the problem ones. Just a couple of swipes with a cutting disk. Running the Cab Forward slow you could see it start to catch then you would have the problem. The thing is this did not happen on all turnouts of the same brand. Yes the wheels have been checked with a gauge. The only other steam I have are a Atlas Shay and Bachman K4(sound) both of those never had problems.


 Againtrains;

Thanks for answering my question. I'm glad you were able to fix your problems. If the cab forward's wheels all meet the standards in the NMRA gage, as you said, then you are correct about the long wheelbase of the cab forward being part of the problem. A K4 is a Pennsylvania RR 4-6-2 pacific I think (I'm not a pennsey guy) A pacific, and a shay, are both shorter wheelbase locos than a Cab Forward with it's two sets of eight drivers. Which brings up two other questions. First, what frog# or what size, are the turnouts? Your "standard Atlas" is a 19" radius and maybe equivalent to a #5 frog. Pecos don't use frog#s just small, medium and large. Your Atlas custom line should have a frog#, probably #4 or #6. The reason I ask is that, like the sharpness of a track curve, the Frog# (or small med, large size) can be a factor in how big a locomotive will go through that turnout reliably.

Though I caution people not to cut frogs, I can't argue with success. You got things to work, and that's great. The thing that sort of puzzles me is why you had to cut the frog wider at all? Virtually all commercial turnouts, regardless of brand, have frog, and guard rail, flangeways that are both extra wide and extra deep, right from the factory. If you measure these flangeways with your NMRA gauge, you should see what I mean. The manufacturers do this to let deep-flanged, or slightly out-of-gauge wheels get through the flangeways without derailing. You probably saw this in action by watching the wheels of your locos going through the frog, when you were troubleshooting. The wheels drop into the frog, and then are pulled back up when they hit the frog point. 
When I make my own turnouts, I build the frog to meet all the turnout standards on the gauge. This eliminates the "drop and then pull back up" behavior, and results in a super smooth passing of rolling stock through the turnout.

My second question is; Did you use your gauge to check each of the critical areas of the turnouts? 

In any case, since things are working well, it's just a matter of curiosity on my part. If you would kindly answer these two additional questions, I'd be grateful. I am very curious.

thanks;

Traction Fan:smilie_daumenpos:


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## Againtrains (Mar 6, 2016)

*Turnouts*

Ok I have used the old, and newer Atlas #4 in yards...not the yard that the Cab Forward uses... Mainline is all #6 Atlas or large Peco. I might have a few Med Peco and I know of two curved Peco's on the mainline. 

The problem ones where #6 Atlas and a Peco that I might had warped slightly in install. But now everything works with the Cab Forward. No I did not take the gauge and check the frog afterwards... It was only a couple of swipes back and forth. I had seen some where about using a cutting disk to correct the problem. Yes it does work. Yes the K4 is a shorter wheel based engine vs Cab Forward... I just wanted the Cab Forward because when I was modeling in HO I had one... NOW if I could fine a Camel Back in N Scale I would be happy. Most of my other engines are diesels. I hope that answers most of your questions.


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## traction fan (Oct 5, 2014)

*Thanks again, Againtrains*



Againtrains said:


> Ok I have used the old, and newer Atlas #4 in yards...not the yard that the Cab Forward uses... Mainline is all #6 Atlas or large Peco. I might have a few Med eco and I know of two curved Peco's on the mainline.
> 
> The problem ones where #6 Atlas and a Peco that I might had warped slightly in install. But now everything works with the Cab Forward. No I did not take the gauge and check the frog afterwards... It was only a couple of swipes back and forth. I had seen some where about using a cutting disk to correct the problem. Yes it does work. Yes the K4 is a shorter wheel based engine vs Cab Forward... I just wanted the Cab Forward because when I was modeling in HO I had one... NOW if I could fine a Camel Back in N Scale I would be happy. Most of my other engines are diesels. I hope that answers most of your questions.


 Againtrains;

Yes it does answer my questions thank you very much. B.T. W. I know the frog flangeway that you widened a bit would not meet the gage spec. After all it was wide to start with. I was thinking of the guard rail flangeway and the spacing between that, and the frog flangeway. However, that's not important since everything is working well. Therefore "If it ain't broke" etc.

An N-scale camel back? I don't know of one. Bachman seems to have the widest selection of N-scale steam. If there is no commercial model available, it would make an interesting kit-bashing project.

regards;

Traction Fan:smilie_daumenpos:


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