Layout and track expansion and contraction.

I saw that too, pretty crooked after the expansion. I would guess it was in an un-conditioned space, but it's just a guess. I have a few small gaps, but they were not done on purpose, just worked out that way. Most of my track is butted up pretty tight. I have Atlas track and switches. I don't think mine matter much because the layout is in the basement which is a conditioned space year round.

I had a track that is isolated for a separate circuit connecting to a Ross  switch and the fit was so tight that on a hot day the two center rails touched and powered the other track so I had to cut 1/32 inch to create a gap where the nylon pin goes.I built this part of the layout when the average temp was 50 degrees.

Mikey

...so don't forget to preheat your track in the oven ....

If he had brass rails it's really understandable; it expands like mad.

  Having done a fair bit of welding, and plumbing with long lengths of pipe, thinking of thermal expansion is always on my mind when building.

My layout has a lift bridge (hinged one side) that was fabricated in the wintertime. Everything worked well. Then the trains were not run for the next 6-7 months. When I did get ready to run them, the bridge would not close. The layout wood had expanded over 1/4". I actually had to saw that amount off of the bridge rails and base so the thing would work once more. I'm familiar with transverse-grain wood expansion from humidity, but thought there were plenty of wood joints and gaps that would make that a non-issue. To this day, wintertime operation is fine; summertime operation, a little sticky. BTW, a humidifier is mandatory in the summer.   

For track, I use conventional tubular (many joints) and Gargraves in several places. I figure the track joints will have enough movement to take care of the table expansion, but do wonder if sometime down the road there won't be an issue of diminished electrical continuity. So far, all seems okay.

Neil