track plans

[Yampa Bob]

Terry
Very well said, and thank you. 

As I read through my Atlas track catalog, in the "Snap Track" section, I see expressions such as "The choice of discerning modelers",  "Discriminating modelers of all skill levels" etc.

Nowhere does it say "For toy trains only."  Atlas has been making HO track for over 50 years.  They recently upgraded all their turnouts by eliminating the rivets, replaced stamped points with actual rail stock, improved the frog point, decreased the flangeway length from .25" to .12", and added more undercutting to stock rails for smoother divergent point transition.  Of course, those who laboriously build their own turnouts might still consider these turnouts as "toys."  Therefore if someone has a layout with 100% flex track but also uses "Snap-Turnouts", that seems to be a contradiction. 

As for being "prototypical", few railroads if any, lay track in 261 foot sections. They may weld shorter lengths to form "continuous" pieces, but they traditionally still lay "snap track" with rail joiners.  

As often stated, "Beauty is in the eye of the beholder."

NewYorkCentralGirl,
Banking on curves only helps reduce lateral forces (centrifugal and acceleration) to allow greater speed, just like on a race track. However the bank in combination with greater speed also increases "G" forces.  All other dynamic forces still apply

[NewYorkCentralgirl]

Yampa bob,
thanks for the info

[Yampa Bob]

You're welcome, I hope all your concerns have been answered. Don't be discouraged if it takes a long time to figure out a suitable layout.  For some of us, it's a lifetime endeavor.

Have fun

[pdlethbridge]

You could use easements  leading to a tunnel or behind buildings where the radius could be reduced. This could be effective for all hidden curves. Exposed curves could be the maximum allowable.

[Yampa Bob]

On a model track, I think the main place where an easement is helpful is transition from straight track into the divergent turnout point. This transition is rather uprupt, and a major cause of model derails at excessive speed.

Resultant lateral forces increase dramatically at this transition, causing wear and damage to real railroad wheels and points.  AREMA, through the auspices of the FRA, have been correcting this problem by changing out turnout components to a lower entry angle, with a longer curved point. 

The maximum speed for a standard #20 turnout, which has an angle of only 3 degrees,  is 45 mph.  With a lower entry angle speeds have been increased to 55 mph with reduction in resultant lateral forces.  Changeouts of components on NJT have shown a dramatic decrease in wear and damage.

Turnouts here in the mountains and many freight yards have high divergent angles, often exceeding 8 degrees.  Rio Grande addressed this issue in the 50s or earlier by using short curved points.

If you examine a Bachmann turnout, you see the divergent point is curved, compared to the straight point used on Atlas turnouts.

On an Atlas turnout, there are actually 2 abrupt changes, one at the tip of the point, another at the pivot.  Also, with the straight point, there is .02 variance in track gauge through the point length. They increased the straight rail undercut, but the abrupt change is still a factor.


For a read on the AREMA research:
http://www.fra.dot.gov/downloads/research/rr0610.pdf

[pdlethbridge]

If you also factor in all the variables of installing turnouts and the accident rate will increase dramatically. Switches should be mounted flat, no bows, tracks leading in and out smooth and level to the switch. All track should be correctly gauged, that means not over hammering the nails that hold down the track as this will narrow the gauge and cause a hump.

[NewYorkCentralgirl]

even though the superelevated tracks arent needed the september issue of model railroader had an easy way of doing it so i think i might add them in just for appearance

[pdlethbridge]

I superelevate the track by putting in a stripe of.020 basswood under the outside rail. It can't be seen under the rail and it gives the loco a nice appearance going through the curve

[jsmvmd]

Dear NYC Girl,

Others can correct me if I am wrong, but I believe the gist of posts from a few years back was contrary to superelevation for model rr's. 
The reason is it is not needed and might contribute to derailments, unless the trackwork is perfect.

Am I right, folks?

Best Wishes,

Jack