I received an e-mail from a gentleman who purchased a copy of Detailing Track. Nicholas wondered whether or not to file away the inside flange on the stock rails of his scratchbuilt turnouts. He noted that the prototype doesn’t do this, and it seemed from the book photos, that I didn’t either. Yet the instructions that came with his Fast Tracks jig said to file this flange away. He raises a great question, one that I took for granted everyone knew the answer to. I was dead wrong in my assumption, so let’s look into the subject.

Filing away the inside flange on the base of the stock rails at switchpoints is a decades old hobby practice used by manufacturers and scratchbuilders alike. While I’m guessing here, I suspect it simply makes construction easier, in that filing a flat surface on the back of the mating switchpoint is a simple matter. Unless you get sloppy with the file, it doesn’t detract all that much from the finished turnout in terms of the realistic appearance. Conventional wisdom once used this surface area and contact point as part of the electrical path through the turnout, a practice that we now understand has many drawbacks. There are better ways to provide a bullet proof electrical path through a turnout that doesn’t rely on the physical contact between the switchpoint and stock rails.

For those who still prefer rock it old school, the process is simplicity itself. You file down the flange at the base of the rail for a distance of several inches until you get even with the web of the rail. This also takes off a portion of the inside rail head, which creates the tapered flat surface and a small notch for the switchpoint to snuggle into. A similar flat area is filed on the inside of the switchpoint along with filing a taper onto the gauge side of the switchpoint rail head. This makes a nice sharp point that most equipment wheels won’t stumble over. I’ve built turnouts from scratch in HO and O scales since I was a teenager, using this process countless times on codes 70, 83 and 100 rails. It’s simple to learn and practice makes perfect, or pretty darn close.

Rail flange filed away

Switchpoint filed flat on inside

File a flat surface on the inside of each switchpoint, leaving a portion of the rail web.


Finished switchpoint

Taper the rail head on the gauge side of the switchpoint to create a smooth transition.


A knife-like point on the end

A knife-like point on the end will not trip up any wheels through the turnout.


A snug fit is what you want to see

With care and patience, a scratchbuilt switchpoint should snuggle in nicely to the stock rail providing a smooth path for wheels to follow.

Today, I prefer to use commercial castings from American Switch and Signal for both switchpoints and frogs. The beauty of these is that filing away any flange material on the stock rails isn’t required, since they are designed to fit the profile of the stock rail like the prototype points seen here at Brookville on the I&O.

Switchpoint Brookville IN

In addition to having a prototypical profile, these castings also include a wealth of detail like the reinforcing bars on both sides, rivet details, the joint bars at the heel where they attach to the closure rails, along with switch and back rod clips.

American Switch & SIgnal switchpoint in code 100

American Switch & SIgnal switchpoint in code 100

They do require a bit of cleanup to both sides of the end of the tapered rail head. At least I do this on mine, as I prefer a nice clean, sharp edge for a seamless fit and smooth tracking. In the next photo, you can see how they fit around the flange of this piece of code 100 rail without any modification.

Against the stock rail

A test fit against the stock rail. Nothing was done to either piece.

Test fit

Of course you could also file regular rail in a similar fashion by removing the bottom corner on the inside surface, and tapering the top of the rail head just a little, allowing it to fit around the unmodified stock rails. Experimentation and patience is key.

I’m not at all familiar with the Fast Tracks system or jigs except for understanding they are popular with modelers for the predictable results they give. I prefer to use the castings for their ease and superb details. I’m not saying one is better than the other. It depends on what your objectives and resources are.

Any questions, feel free to ask.