Smoothing Track Segment Transitions

What kind of track are you referring to?

I have a combination of Ross and Gargraves Flextrack. 

Nice. The pins have dimples to prevent pin going all the way in. This prevents both rails from meeting. You could lightly tap the other end of the rail or use a wooden block.

Also, on gargraves, end of the rail dips due to manufacturing.  Put two tracks together and put a straightedge on there and see the dip.

I use gargraves and ross at home and at the club. I tapped some rails together and left others. Matter of preference. 

I never knew until a few years ago the proper method for assembling Ross or Gargraves track.  

This is the method:   Take the connector pin and insert it into the opening in a section of track.  Tap it into the opening until the bump is inside the opening.  Do this procedure with the other two pins.  

Then take the adjoining track and connect it until the pins are completely inside the opening.  That eliminates the gap between track sections.  

Thank you all for the responses. That pin trick should help immensely.  I was curious as on the curved pieces the bump was fully hidden and they were smooth as can be !

Why is it necessary to eliminate the gap ?   I understand that large gaps, a sixteenth of an inch or more, should be closer, but why bull tight ?

Dan Padova posted:

Why is it necessary to eliminate the gap ?   I understand that large gaps, a sixteenth of an inch or more, should be closer, but why bull tight ?

Agree! There is no need to tap the pin in so the bump disappears into the rail. What you're actually doing when you do this is bulging the rail and you still have a bump.  The purpose of the bump in the rail joiners to make sure it doesn't slide all the way into one side of the rail or the other. It is not meant to be hammered in.

For the most part the gaps in the track do not bother me and for all my switches they are intentional for the non derail.  It was mostly for the tunnels and hard to reach section as an attempt to have the trains run as smoothly as possible.  As with most things though I am quite possibly being too obsessive.  

Dan Padova posted:

Why is it necessary to eliminate the gap ?   I understand that large gaps, a sixteenth of an inch or more, should be closer, but why bull tight ?

By eliminating gaps you reduce the chances of tearing up your traction tires.

A small gap between track sections is desirable should the track expand under certain conditions (temperature change, humidity , etc.). Bumps in pins are there to prevent track distortion under said conditions.

Personally I hate rubber tires.  If you choose to embrace that Faustian bargain, know there's a price to be paid.  But gaps as you describe will also create a "snag" which can destroy slow-speed realism.  Especially if you used Gargraves flex track and weren't fastidious about eliminating kinks, when the first driving axle hits that snag, you'll see a little lurch, or the loco might even stall if it's running slowly enough.

I filed down those bumps or "shoulders" on every pin, leaving just enough to create a little friction when inserted in the rail.  Then I tapped my track sections together until the rail-heads were flush.  Major pain in the butt!  I love Ross track, but i wish they had a better design for the pin.

They used to make track dressing stones for leveling. Like a rubber eraser but made of abrasive; stonelike, very course (like#100-150) to fine(#300-400). Gramps gave me some for slotcars as the AFX version was small and the O size did all AFX rails in one pass. I never used them much for O except on Gramps GG layout, he did most of those joints. Lengths had very slight gaps (1/64-1/32" maybe; more gap on the end pieces (30')

Expansion would be my concern butting rails tightly. Yes,there will be expansion and contraction so your curves must float some(less attached to the layout) or long straights must allow for a flex laterally as the rails grow in length. ( length vs temp change in various metals is fairly easy chart research; track rails are one I never had to know well. I'd guess at an 1/4" longer for 20' between cold nights not on, and hottest day with heavy electric draws on the rails. (Dont forget that wood frame layout may grow too, and a different rate than track)

Smooth track isn't an impossible dream imo though. Wear of everything; even steel will be less; click clack less pronounced, letting electronic sounds do their jobs; better slow running.... go for it 😉

Expansion?  Sorry but I doubt it. Unless you store your O-gauge layout in totally uncontrolled conditions, in which case you probably should have chosen LGB 

Real RRs like the CSX have issues with expansion, sun kinks, etc., when direct sunlight heats steel ribbon rail over hundreds of yards.  The rail profile and elasticity of materials involved is very different.  This isn't going to happen to any measurable extent on a 4x8 in your spare room.  Or even on a 40' layout in a basement with temps ranging from 50-80, not gonna happen.   If the gap is 1/8" and the longest track section is 40", you're talking an elongation of 0.3%.  Google the properties of steel and see what kind of temperature change it takes to achieve that kind of elasticity.

Now- if you use Homasote or some kind of paper substrate for the layout base AND you don't do a good job controlling humidity in the room, you might eventually experience some swelling.  That may result in bellies or kinks, and could affect your trackwork even if you DO leave a gap between track sections.  In such cases you should do yourself and your trains a favor, and install a dehumidifier!

Think about it... If you put one screw in each 3' section (or if you glue your track and roadbed to the sub-terrain), then it can't really "slide" to take advantage of the "gap" anyhow.  So why leave a gap?  I'll tell you why... because it's a pain in the butt to file down all of those pins!

The bump on the pin is mostly a manufacturing artifact from where it's attached to the sprue.  Also, it's there to ensure good contact with the inside of the hollow rail.  Perhaps it's also there to prevent the pin from going all the way into the rail end, and getting "lost" when joining two sections together.  But it's not there to facilitate expansion of adjacent track sections.

If you don't file down the bump, and you build a layout with gaps, it will definitely be hard on the $%^#& tires.  What's worse, some locos' wheels may snag in the gaps and lurch or stall at very slow speeds.  I love Ross track and switches.  But like pistachio shells, the bump is just a nuisance.  I would pay 3x as much for pins that are already filed to fit smoothly with a little resistance.  It's your layout folks, so build it however you want.  I just encourage you to think critically before deciding.