On the first couple of loco kits that I built, I followed the instructions and soldered nickel-silver wire into the handrail knobs. I soon decided this was unsatisfactory, for two reasons. Firstly it was all too easy to hold the loco with the fingers pressing on the rails, which were very easily bent, and secondly the effort involved in removing solder from the join was substantial. Using an Resistance Soldering Unit (RSU) and solder cream produces less excess solder, but it also risks burning pits in the knob or the wire.

Because I am of an engineering bent I looked for a better approach. What I fixed on was using piano wire for the rails because it is fairly bombproof, and using Loctite 601 Retainer to hold the rails in the knobs.

This is how I do it:

1 Ensure the holes for the handrail knobs are opened up to be a good close fit on the knobs.
2 Prepare a piece of piano wire of the right size to act as a temporary alignment tool. For short rails that are only two or three knobs long it might well be the handrail itself, but for longer rails (e.g. boiler sides) use a length that covers at least three knobs, but is not so long as to be unwieldy.
3 Slide two knobs onto the wire and insert them into the first two holes. Fix the knobs in place by appropriate means.

For fixing in whitemetal Loctite is good, as is cyanoacrylate glue or epoxy. For etched brass, soldering from the inside is best if you can reach it, or use an RSU (carefully) for minimum cleaning, or soldering iron for lots of cleaning.

4 Proceed along the line of knobs using the piece of wire to ensure all the holes in the knobs are in the correct line (which isn't always straight).
5 When all the knobs are in place, and any glue has set, prepare the real handrail. Cleaning the cut ends of piano wire with normal files is a recipe for spoiled files. I use diamond files. Many of the usual suppliers stock them, but I buy mine from Arc Euro Trade. www.arceurotrade.co.uk
6 When ready slide the wire into the line of knobs. Once you are satisfied it is exactly in place, pick up a small drop of Loctite Retainer on the point of a needle and gently stroke it along the joint between knob and wire. Do this for each knob.
7 Now go away and leave it alone for 10-15 minutes and then wipe off any excess retainer with a piece of tissue. That should complete the job with no need to clean the fiddly joint between knob and wire.

I use Loctite 601 Retainer. I have a tiny bottle that is still going strong after over 20 years (not even kept in the fridge), but any of the retainers or high strength retainers will do (do not try to use the threadlock or nutlock ones because they are deliberately weakened to allow removal).

There are other brands (Tru-Loc is one), which are also just as good.

The photos show the handrails on my current construction project (a David Andrews A2). For the smokebox handrails where the knobs are soldered a little cleaning up was required. Otherwise no cleaning up was necessary, apart from a quick wipe with a tissue. I think this is a lot easier than scraping off solder. The result is very strong; you can pick up the whole loco by the handrail. Even the lamp bracket on the smokebox door was fixed using retainer.

Anaerobic retainers like Loctite only work where there is a shaft to fit in a hole (or a screw into a nut or female thread). They work by polymerising in the absence of oxygen (hence the anaerobic name ) and leave an interference fit. It does not have sufficient peel strength to stick adequately to a flat surface. The advantage over superglue is that it gives you time to locate the joint accurately, and it wicks well into the joint. These retainers also have a long a huge shelf life.

Are there any disadvantages? None that I can think of for the Loctite, but the piano wire is difficult to bend for curved handrails.

Annealing the bend areas by heating to red heat and cooling slowly helps somewhat. Piano wire can be bent, but if you get the bend in the wrong place, you may as well forget it and start again. You can always use the straight bits for shorter rails elsewhere.