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Broadway Limited Imports Pennsylvania Railroad T-1 4-4-4-4 Duplex Derailment Troubles

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Broadway Limited Imports Pennsylvania Railroad T-1 4-4-4-4 Duplex Derailment Troubles
Posted by cascadenorthernrr on Thursday, March 16, 2017 7:52 PM

Hi, I got a BLI PRR T-1 and at my club the loco keeps derailing as it goes through a section of superelevated track. I spent about 20 minutes observing the loco running back and forth over that section of track till I came to the conclusion that the front driver truck does not have enough "play" to traverse slightly superelevated track without the front drivers jumping the track. How can I add some "play" to the truck to allow it to navigate the turn?

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Posted by mobilman44 on Friday, March 17, 2017 5:50 AM

I don't recall you mentioning you were in an MR club.  Have some of the members looked at your problem loco?   BLI typically makes high quality stuff, so perhaps it is the track.

Have to say, it seems odd you would have a wonderful loco like a BLI T1 and not have a layout or other MR "stuff". 

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, modeling the "postwar" Santa Fe and Illinois Central 

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Posted by BMMECNYC on Friday, March 17, 2017 6:53 AM

mobilman44
I don't recall you mentioning you were in an MR club.

It was in one of his other threads.

mobilman44
Have some of the members looked at your problem loco? BLI typically makes high quality stuff, so perhaps it is the track.

I would ask them to take a look at it.  Does anyone else have a T1 they can run through the section of track in question?   What is the radius of the curve in question?  How was the transition accomplished?

The T1 is a ridged frame model.  There is very little play in the locomotive drive train.   As far as I know there is not a way to make the front set of drivers articulate.  You might check to see if the pilot truck (the first set of 4) is tracking properly and is not picking the locomotive up slightly (I have seen this happen with other locomotives, but not necessarily the T1).  It is entirely possible that there is a track issue, especially if the track was not laid with long ridgid frame locomotives in mind. 

I would not recommend hacking up your T1.

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Posted by mbinsewi on Friday, March 17, 2017 7:51 AM

That's quite a locomotive.  Not cheap.  Not that I know anything about it, but I had to "look it up" on the net, just to see what it is.

I did find this review in the August, 2013 MRR.

http://mrr.trains.com/news-reviews/staff-reviews/2013/06/video-broadway-limited-imports-paragon2-ho-scale-pennsylvania-rr-t1

It does seem like a track problem to me.

Mike.

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Posted by BRVRR on Friday, March 17, 2017 8:42 AM

We've had a BLI Pennsylvania T1 on the BRVRR since Christmas of 2013. The manufacturer recommends a minimum of a 22-inch radius curve. It is a stellar performer on the 22-1/2 inch outer mainline, but binds a bit on the inner 20-inch main.

The BRVRR layout doesn't have any super-elevated track, but the loco is picky. Any irregularity will cause the front truck to derail, followed by the lead drivers.

I would bet that there is some flaw in the track work, particularly if the loco derails in the same place repeatedly.

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Posted by 7j43k on Friday, March 17, 2017 10:51 AM

I think the problem is more likely in the track than the locomotive.

Note that I used the word "think".  Not "know".

I've got some superelevated curves.  First, they're 48" radius.  THAT never hurts.  Also, they also have easements.  THAT never hurts.  And, most of all, the combined easement and approach (ramp) to the superelevation section is 18" long.

The point of the long (18") approach is to have gradual change--no big surprises for the equipment.

There has never been a derailment on those curves.  Never.  That is with my equipment and at least 15 other people's.

 

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Posted by Paul3 on Friday, March 17, 2017 10:57 AM

cascadenorthernrr,
What's the radius of the curve?

How long is the transition from the flat to the superelevation?

How high is the superelevation?

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Posted by cascadenorthernrr on Friday, March 17, 2017 11:08 AM

The club "mechanic" looked at it and he came to the conclusion that the front truck needs more "play" the section of track is a very broad curve (the track barely turns) and everyone elses locos run over it fine so it must be my loco. I must add its not really a superelevated curve more so its a slight bend in the track where the outside rail is a bit higher than the inside causing the loco to jump the track.

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Posted by Water Level Route on Friday, March 17, 2017 11:17 AM

cascadenorthernrr
the outside rail is a bit higher than the inside

That's what superelevation is.

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Posted by cascadenorthernrr on Friday, March 17, 2017 11:35 AM

But its only higher by a few millimeters.

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Posted by BMMECNYC on Friday, March 17, 2017 1:54 PM

cascadenorthernrr

But its only higher by a few millimeters.

 

That is correct.  Thats what superelevation is.

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Posted by 7j43k on Friday, March 17, 2017 2:17 PM

A millimeter is about .04"

A "few" millimeters would be three or more.  Three millimeters is 3 x .04".  Which is an eighth of an inch.

THAT would be an incredible superelevation.

That the curve is only a slight bend and of wide radius does not make it immune from error.  If the locomotive ONLY derails there on the entire layout, I don't think improper track can be ruled out.

One thing that's pretty easy to check out on the loco is to put it onto a FLAT surface.  Then try sliding a piece of paper under each of the driving wheels.  If it slides under one or more, that could indicate a problem.  If it does not, that does not necessarily clear the loco.

 

Clarity over what the leading truck would be is, here, important.  Is it the 4-wheel swiveling lead truck?  Or is it the 4-wheel front engine--the one with the siderods.

 

Ed

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Posted by cascadenorthernrr on Friday, March 17, 2017 2:21 PM

There are some other spots too but this one is the one I observed the most.

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Posted by rrinker on Friday, March 17, 2017 2:42 PM

 As states, the PRR T1 is a rigid frame engine, the two engines (wheels, siderods, and pistons constitute an 'engine' eg a Bog Boy has 2 engines) are rigid and not independent to swivel (on a prototype Big Boy, only one engine swivels, the other is rigidly mounted to the frame. On most models, both engines swivel like a pair of diesel trucks as a concession to tight radius curves). The T1 is nore like a 4-8-4 in that regard. Superelevation works on models (for appearance anyway), but like grades and curves it needs to transition in and out, you can't go from flat to having the outside rail jacked up a couple of millimeters. That much twist will raise a flange above the railhead and lead to derailments. Shorter diesel trucks can tilt and swivel and handle this, as can most rolling stoock with the trucks fastened in a 3 point suspension setup. But the long wheelbase of a steam loco - the track has to be much more carefully aligned. 

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Posted by 7j43k on Friday, March 17, 2017 2:45 PM

cascadenorthernrr

There are some other spots too but this one is the one I observed the most.

 

 

Oooohhhh.  There's other derailment locations, eh?

It could be useful to catalog them.  And to see if there are any unifying characteristics.  Is it curves?  What radius?  More superelevation?  Is it switches?  What size switches?  What location in the switch?  Does it happen only when the loco "curves" to the left?  Or to the right?

Another relatively easy experiment is to remove the lead truck.  That would be the first 4 in 4-4-4-4.  Does it still derail?  In the same way?  It's less likely to be the lead truck, but it does happen.

If it's the loco, the question is:  Why?

And finding that out is a matter of exploration.

Which is also kind of true for the track.

 

 

Ed 

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Posted by cascadenorthernrr on Friday, March 17, 2017 2:51 PM

I understand all that, but the second engine or set of drivers have a little give to the truck so it doesn't derail in reverse.

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Posted by mobilman44 on Friday, March 17, 2017 3:26 PM

Perhaps the "club" members could work this problem better than the folks on this forum..............

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, modeling the "postwar" Santa Fe and Illinois Central 

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Posted by cascadenorthernrr on Friday, March 17, 2017 3:38 PM

Theres no need to get rude. I'm just saying that the problem has been diagnosed already now I need a solution.

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Posted by 7j43k on Friday, March 17, 2017 4:02 PM

cascadenorthernrr

I'm just saying that the problem has been diagnosed already now I need a solution.

 

the diagnosis, I believe:

"...came to the conclusion that the front driver truck does not have enough "play" to traverse slightly superelevated track without the front drivers jumping the track."

the beginning of the solution:

"How can I add some "play" to the truck to allow it to navigate the turn?"

 

 

It sounds like you want more lateral motion in the drivers.  Use of the term "superelevation" might lead a person to desire VERTICAL slack.  I seriously doubt that can be done.  And I seriously doubt that this loco NEEDS that. You can get lateral motion by loosening up the sideplay in any two drivers.  For a model, I think the ideal would be the inner two (of four driving axles).  But I might modify that choice so as not to be working on a geared axle.

Anyway, someone is going to have to disassemble your drive train and figure out how to remove some metal.  The bearings may have to be moved closer together, or possibly some metal will have to be removed from the side of the frame.  A lot of "how to specifically do it" will have to be figured out with the model in hand.  So far, no one here has mentioned that they have done that.  Perhaps someone somewhere has, and can give concrete and specific advice.  And perhaps you will have to do it on your own.

 

Ed

 

PS:  You might try contacting BLI.  They may well be of some help.

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Posted by zstripe on Friday, March 17, 2017 4:29 PM

All it takes is a small dip/rise,even a slight kink in the trackwork......I would not rule that out....before doing surgery on a fine Locomotive......

Take Care! Big Smile

Frank

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Posted by richhotrain on Friday, March 17, 2017 4:42 PM
mobilman44
Perhaps the "club" members could work this problem better than the folks on this forum..............
 
cascadenorthernrr
Theres no need to get rude. I'm just saying that the problem has been diagnosed already now I need a solution. 

 

I don't think that the suggestion is rude, not in the least.
 
First of all, has the problem been diagnosed?  It doesn't sound like it. It could be the club's layout. It could be your particular locomotive. Or, it just may be that a rigid frame with 16 driver wheels needs to be run on a layout with broader curves than that on your club's layout.
 
Second of all, mobilman44 is correct in sending you back to your club. The members can look at the problem first hand, up close and personal, as opposed to the forum members who can only offer guesses and speculation. Take advantage of the fact that you are a member of a club. We should all be so lucky.
 
Rich
 

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Posted by 7j43k on Friday, March 17, 2017 4:51 PM

Rich,

8 drivers.  Not 16.

Steven says he has his diagnosis.  And he's the guy who's got the problem.  A lot of us think he's wrong.  And we've presented our case.  Steven, after all of that, has asserted he has the diagnosis.

I have given him suggestions for work he might do on his locomotive.

The club?  If Steven was satisfied with all that the club was doing for him, he wouldn't have come here.

And, yes, I saw no rudeness from Mobileman.  I think Steven is in error there.

 

 

Ed

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Posted by richhotrain on Friday, March 17, 2017 4:58 PM

7j43k

Rich,

8 drivers.  Not 16.

Oops !  Embarrassed

I must have assumed that Steven already kitbashed two of them together.  Laugh

Rich

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Posted by 7j43k on Friday, March 17, 2017 5:21 PM

richhotrain

 

 
7j43k

Rich,

8 drivers.  Not 16.

 

 

Oops !  Embarrassed

 

I must have assumed that Steven already kitbashed two of them together.  Laugh

Rich

 

 

I guess that would be a TT1.  Yikes!  That would be a beast.

 

Ed

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Posted by richhotrain on Friday, March 17, 2017 9:19 PM

I don't believe that we ever got clarification from the OP as to which wheels he is talking about.

Is it the pilot truck that needs more "play"?

Or is the front set of driver wheels?

Or is he talking about the entire front set of four driver wheels?

Rich

Alton Junction

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Posted by BMMECNYC on Friday, March 17, 2017 9:36 PM

richhotrain

I don't believe that we ever got clarification from the OP as to which wheels he is talking about.

Is it the pilot truck that needs more "play"?

Or is the front set of driver wheels?

Or is he talking about the entire front set of four driver wheels?

Rich

 

It could be as simple as an S curve.  Even an gentle one will cause havoc with those T1s.  One of my club members has a T1, and it derails on the diverging route of a turnout when the track curves back to parallel.  It is a Peco medium turnout with some radius curve starting right after it. 

Also makes me wonder how well the prototype one is going to run when they finish building it.... The N&W's design is far superior solution to the problem the T1s sort of solved IMO. 

Honestly would rather see a NYC Hudson built new.

 

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Posted by tstage on Friday, March 17, 2017 9:50 PM

BMMECNYC
Honestly would rather see a NYC Hudson built new.

You and me both, BMMECNYC...

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Posted by JOHN C TARANTO on Friday, March 17, 2017 11:34 PM

The problem is the locomotive's shrouding and the lettering on the tender.  The locomotive below would have no problem negotiating those curves.  Whistling

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Posted by selector on Saturday, March 18, 2017 2:12 AM

Unless BLI has reconfigured their newest versions of the T1 Duplex, the axles don't need any play.  The two center axles have blind drivers so that the two outer driver axles are the only ones where the flanges keep the train railed.  This leaves this rigid-framed locomotive to run its blind drivers well inboard of the inner rails on a curve, the tighter the curve the more the innerhang. 

My earlier Paragon version with a QSI decoder is a towing beast, and runs very well on tracks that are not bumpy.  My curves were all superelevated, too.

I found that whenever I introduced a new locomotive to my layout, it found a section of track it didn't like.  When I fixed the problem, but so that the rest of the engines would also play nicely on it, everything went perfectly from then on. I would blame the tracks before blaming the locomotive, but until I had a look at it, it's hard to say.

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Posted by richhotrain on Saturday, March 18, 2017 5:37 AM

tstage

 

 
BMMECNYC
Honestly would rather see a NYC Hudson built new.

 

You and me both, BMMECNYC...

 

Love the NYC Hudson.  Yes

The PRR T1 4-4-4-4 certainly would not have been my first loco. Why take on such a challenge, especially on someone else's layout? 

ConfusedConfusedConfusedConfused

Rich

Alton Junction

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