Head rod / Back rod

We modellers tend to call it a throw bar, and we tend to use only one. But as I learned while reading Detailing Track by my friend Mike Cougill (and available through OST Publications*), what we call a throw bar is actually a “head rod”, and points will have one or more additional bars called “back rods”.

I’m building turnouts using a solid point, as opposed to a hinged point. This means the point and closure rail are made from a single piece. At the place where the point would be hinged, the rail is soldered to a printed circuit board tie. The end of the point is then soldered to the head rod. The rail simply bends slightly when the switch is thrown. This system works and the points are guaranteed a good electrical connection since wires can be soldered to the closure rails.

Normally, a standard PCB tie is used for the head rod, but I thought an S scale tie would be too massive. So I ordered a selection of switch-length PCB ties from Tim Warris at Fast Tracks* and then my friend Chris Abbott and I did some experimenting.

We decided to use an HO scale narrow gauge tie for the head rod, and an N scale tie for a single back rod. Locations for each were marked with the turnout in place on the layout, to ensure that the rods would fall between the appropriate wooden ties.

While the HO narrow gauge tie looks much better as a head rod, it’s too thin to accept the piano wire throw from the Bullfrog mechanical switch machine I intend to use:

Drilling a hole large enough to clear the wire would seriously weaken the head rod.

Fortunately, Chris came up with an elegant solution. He cut and fettled a thin strip of brass to solder to the bottom of each head rod. He then drilled a clearance hole for the piano wire, offset on the brass strip. Head rod and strip were tinned, soldered together, and the finished assembly was brush painted a black-grey.

The head rod and back rod can be seen in this photo:

Head rod and back rod.

After the turnout is installed on the layout, I will detail the head rod with NBW castings and other goodies to make it look more prototypical. As a bonus, the brass strip moves the hole to the bottom of the head rod, instead of the top, so we should be able to cut off the switch machine wire below the level of the tops of the ties.

The turnout with head rod and back rod in place can be seen set in place in this photo:

Turnout on ties. Head rod and back rod installed.

Here is a photo of another turnout with head rod and back rod, plus grass growing between the ties. The rods can be seen, but don’t leap out and shout “Train Set!”

Turnout in the grass.

I’ll finish painting the head rod after I install the switch stand. I hope to use the much-missed Alder Models stands with operating targets, which will require soldering an actuating rod to the head rod.

I am very close to being ready to spike down some track!

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