How to Lay Flex Track for Model Trains

What Is Flex Track?

Model train flex track
The Spruce / Ryan C Kunkle

Working with individual track sections has its convenience, but for free-flowing original track designs, flex track is a better option. Working with flex track takes some care and practice but with a little patience and know-how, even a beginner can pick it up quickly.

Flex track is a bendable track section that can be shaped to any radius. One rail is fixed while the other slides in the cradles. Sections come in 18 to 36-inch lengths in most scales. Narrow gauges are available too.

Build a Strong Foundation for Flex Track

This joint on a superelevated curve has soldered joiners, spikes and plastic shims under the ties of the outside rail.
The Spruce / Ryan C Kunkle

With any track, you want to support it well.

Benchwork

Make sure your train table or benchwork has a firm, even surface. If you have changes in elevation, make sure they transition to level smoothly. If you have seems on the tabletop, make sure they are completely level and well supported.

Map your track centerline carefully along the surface. A yardstick works well for straight sections. Curves can be mapped by making a trammel from a yardstick or string attached to a point at the center of the circle.

Roadbed

Some sectional track has a plastic roadbed already attached. Obviously, that can't be done with flex track, but there is a good alternative. Several companies make ​roadbed from cork and foam. Roadbed should provide a smooth but firm cushion for the track.

Split the material down the center and then lay the halves along the centerline of the track. You can buy shaped pads for switches, or simply cut and splice the roadbed.

Tip: Profile rough cork edges with a rasp and fill any voids with drywall putty before laying track to make ballasting easier later.

Preparing the Flex Track

Model train flex track and rail nippers
The Spruce / Ryan C Kunkle

Most manufacturers’ track has ties attached to the ends of the rail. Removing the last tie at each end will make it easier to install rail joiners. Save the ties, file down the molded cradles and reinsert under the finished joint to preserve the look. Make sure the ties slide under the joiner without raising it, creating a rough joint.

Tips

  • Lay switches first, then curves, then finish with straights.
  • Take your time and test the track as you go with a few reliable cars. It is easy to make fine adjustments.

Laying Straight Flex Track

Model train flex track and steel straight edge
The Spruce / Ryan C Kunkle

Why would you want to use a flexible track to lay a straight section? Flex track sections are generally longer than rigid pieces. You can reduce the number of rail joints and the time and materials needed.

The only trick to laying flexible track straight is keeping it from bending. A steel straightedge will help keep everything aligned. Simply hold the straightedge against the web of one rail.

Tips

  • Place the straightedge against the rail itself for a reference, this eliminates potential kinks from any extra burrs or flash on the plastic ties.
  • To secure the track, press track nails or spikes through the molded holes in the ties. If there are no holes, or if you need to add more, use a No. 60 drill bit in a pin vise and drill through the tie. Once the track is properly aligned, tap gently into place with a hammer and nail set.
  • Don't overdrive spikes. The spike/nailhead should just rest on the top of the tie. If you create a depression, you're going too far.

Laying Curved Flex Track

Model train on track
The Spruce / Ryan C Kunkle

Curves present two challenges. First, the inside rail will end up longer than the outside. Second, a kink can easily develop where two curved sections join as the track tries to spring back to a straight shape.

Cut

The first challenge, uneven rails, can be remedied easily with a pair of rail nippers. These special flush-cut pliers are available at hobby shops and are specially designed to give a smooth cut in model rail. Don't use them on wire or other products.

Arrange the track section so the loose rail is on the inside of the curve. Bend the track to shape and the rail will extend beyond the last tie. Nip the inside rail off even with the outside rail with the nippers. Spike the track, leaving the last 3 to 6 inches loose if the curve will continue through the joint.

Solder

Soldering can be intimidating at first, but it is essential to smooth track. To prevent a kink at the joint, join the next section while the joints are straight. Apply a small amount of solder flux to the rails and solder both together at the joint. Using flux and working quickly, you can solder the rail without melting ties. File off any excess solder.

Now continue bending the curve through the joint and on to the next. You can further improve your curves with easements and superelevation.

Once you've laid your track, you'll want to finish with some paint and ballast.