Kato Mikado plus Atlas C55 turnout issue

[mike_lawyer]

Hey guys -

Need some help with a problem I am having.  I am laying the track for my new layout, using Atlas Code 55 track and #7 turnouts.  I have two Kato Mikados with the revised driver's and wheels that work great on C55 track.  I have converted both Mikados to PRR L-1s using GHQ kits. 

For both Mikados, I am having problems running them through Atlas C55 #7 switches.  For each one, when the drivers go through the frog, the drivers on the frog side want to lift up out of the track.  The switches are on a straight, level area.  I had the same problem with two Fast Tracks handlaid switches that I had previously installed in the same area.

This is very perplexing, as I have never had problems with Kato Mikados and switches before.  Has anyone had a similar experience with Atlas C55 switches and steamers?

I had previously planned to use Fast Tracks switches for my layout, but I had some problems with them as well, hence why I went back to Atlas C55 switches.

[peteski]

Have you verified (using NMRA or MTL gauge) that all locos wheels are in proper gauge?  Often, N scale locos are tight in gauge, and Atlas turnouts are not forgiving of that.

EDIT: This will especially be apparent for locos that have long wheelbase in a stiff frame (like 4 drivers in the Mikado)

[nickelplate759]

What @peteski said - it sounds like your drivers are not correctly gauged.

If the tender wheels don't derail it's almost certainly the gauge of the drivers.

[thomasjmdavis]

Does this happen for both the straight route through the turnout and the "switched" route through the turnout?  And does it happen in both directions?

In addition to the suggestion to check the wheel gauge, you might want to check the track gauge all the way through the turnout.  I had a similar problem with a single Atlas turnout on my last layout- turned out the closure rails were slightly bent- causing the turnout to be out of gauge.  My F units navigated it without issues, but PA's often lost the lead wheelset, and some passenger cars would bounce out, or at least wobble badly.  Predictably, I made things worse trying to fix it, and ended up replacing the turnout.

[nickelplate759]

@thomasjmdavis raises a good point.   We shouldn't assume that the turnout isn't also incorrect.  In situations like this it's a good idea to check both the wheel gauge and the track gauge - more than twice I've had both be off, for example a turnout that's a little tight might be fine until it meets a loco that's a little wide.

[prr7161]

I had the same problem with a Kato Mike on handlaid (FastTracks) switches.  Turned out the rear driver set was out of gauge - too narrow.  The locomotive wanted to walk up on to the wing rail.  Most commercial switches are engineered with looser tolerances than strict NMRA guidelines; FastTracks templates are not.  They find gauge problems pretty quickly...

[robert3985]

If your other engines work on the turnouts and it's just the Kato Mikes that hop on the frog, it's almost certainly a driver gauge problem on those particular models.

I hand build all of my turnouts to a "tight" NMRA standard, and so I have to check each and every one of my new engines before running them on the layout because if the turnouts are REALLY NMRA compliant, then engines and rolling stock being perfectly gauged is necessary.  So far, in the 30+ years I've been building my turnouts, I've only had three brass engines and all of my Kato FEF's that didn't need any gauge adjustment. 

If the "check gauge" between the guard rail and the corresponding railhead on the frog...is exactly properly gauged, then an out of gauge engine will "hop" on the frog.  It doesn't make any difference if the route is diverging or straight thru since the "check gauge" is between the guard rails and the frog...so, there are two "check gauges"...one for either route, and they may not be identical.

Since I meticulously check all of my turnouts' clearances as I'm building them before installing them, I don't have a regimen for checking clearances before installing RTR turnouts...BUT, if I were using RTR turnouts, I would check each and every one of them to make sure they were properly clearanced before installing them using my trusty NMRA N Standards Gage.

I never assume that an engine is properly gauged.  I always assume my rolling stock IS properly gauged.

Works for me!

Cheerio!!
Bob Gilmore

[mike_lawyer]

You guys are great.  I figured it out.  When observing the engine from the other side of the turnout, it was clear that the 4th driver (the traction tire driver) was picking the guardrail.  Got out my NMRA gauge, turns out that driver was too narrow.

The other Mike had the exact same problem - the traction tire driver was too narrow, while the other drivers are in gauge.

Oddly enough, both traction tire drivers I ordered directly from Kato parts a couple of years ago.  So I guess the traction tire drivers for whatever reason are slightly narrow.

To fix it, should I just use a screwdriver between the frame and the driver to slightly move the driver into gauge?

[mmagliaro]

It is extremely common for locomotive drivers and other loco wheelsets from almost any commercial source to be narrow.  And it shows itself more extremely on steam locos because they have long rigid wheel bases (i.e. 4 drivers in a row, in this case), so they are much less forgiving than a 4-axle diesel whose trucks can pivot through the curved sections of a turnout.
I'd STILL check the rail gauge all the way through your turnouts.  Atlas #7's were notorious, for me, for being too narrow through the points, making steam locos climb up and hop out with aplomb.  Fixing the Kato driver set may have made things fit through there for this particular engine, but it would be best to know right now if you have a turnout issue that's going to crop up on some other engine some day.
(All I can say is that since I replaced my Atlas curved turnout with a FastTracks, Max is a happy camper)

[mike_lawyer]

It is extremely common for locomotive drivers and other loco wheelsets from almost any commercial source to be narrow.  And it shows itself more extremely on steam locos because they have long rigid wheel bases (i.e. 4 drivers in a row, in this case), so they are much less forgiving than a 4-axle diesel whose trucks can pivot through the curved sections of a turnout.
I'd STILL check the rail gauge all the way through your turnouts.  Atlas #7's were notorious, for me, for being too narrow through the points, making steam locos climb up and hop out with aplomb.  Fixing the Kato driver set may have made things fit through there for this particular engine, but it would be best to know right now if you have a turnout issue that's going to crop up on some other engine some day.
(All I can say is that since I replaced my Atlas curved turnout with a FastTracks, Max is a happy camper)

Max -

I was really surprised that the Kato driver was not in gauge.  Usually Kato is pretty good about gauge.  Bachmann steamers I have frequently found to be too narrow.

With regard to Atlas Code 55 switches, have you had any problems with the straight number 7s, or just the curved turnouts?  So far, I have found the #7s to not be a problem.

Mike

[peteski]

Yes, like Max and I mentioned it, commercially produced engines (Kato, Atlas, etc.) are very often narrow in gauge,  I'm surprised that non-TT drivers in that Kato were gauged correctly. Is it possible that you adjusted them in the past?  I have a pristine Mikado, but I can't get to it now to check.

Atlas (and also handbuilt and likely ME turnouts too) have tighter tolerance than standard C80 turnouts, so out of gauge wheels will have problems on those.

With problems like this, wheel gauge is always the first thing I check (and as others mentioned, track gauge of course).

[mike_lawyer]

Pete -

I had never checked the gauge of the first three drivers and had not touched them, and they were perfectly in gauge.  I guess it's possible a prior owner put it in proper gauge.

[mmagliaro]

Max -

I was really surprised that the Kato driver was not in gauge.  Usually Kato is pretty good about gauge.  Bachmann steamers I have frequently found to be too narrow.

With regard to Atlas Code 55 switches, have you had any problems with the straight number 7s, or just the curved turnouts?  So far, I have found the #7s to not be a problem.

Mike

Nearly all my Mikados have had some narrow drivers.
As for the #7's, OY... except for maybe 3 or 4, all the #7's on my layout had to be corrected for gauge.  I have posted  photos numerous times in here of the typical "narrowness" I found through the point rails, so what the heck, here they are again.





The curved turnout was worse because it was more unstable, and correcting the gauge is harder with curved rails.

[peteski]

Mike's original problem description states that the derailment happens at the frog area, not around where the points are.  He also mentioned that those locos also had a problem when going through FastTrack handbuilt turnouts.

But yes, Atlas C55 turnouts do have their own gauge issues at the points.

[mike_lawyer]

So for locos that have drivers that are too narrow, what is the preferred method to getting them in gauge?  Is it just using a screwdriver between the frame and the back of the driver to slowly work it into place? 

I have two Atlas C55 #7s currently set up on the layout, and I will measure every one I put down with an NMRA track gauge.  So far, the two that I put down points appear to meet NMRA standards.  Checking them first with an NMRA gauge before installing them is a great practice.