Installing Catenary Masts
Installing Catenary Masts
A question that often gets asked how do i install catenary masts? How far a part should they be installed? There are various catenary ranges available such as Peco, Dapol etc & recently released Scalemodelsecnery.co.uk OHLE gantry spans. The catenary systems such as those by Peco, Dapol have a range of different length wire packs. These range from long wire packs for straights right down to shorter wire packs for going around curves etc. Some continental catenary systems such as those by Marklin, Viessmann offer catenary wire packs for fitting above track work cross overs etc.
In the image below can be seen a typical range of different length catenary wires offered. These usually have pre-bent hooks on the ends of the wires for hooking onto the mast registration arms.
The general rule of thumb for fitting the masts is to use the longer wires on the straights such as Peco’s LC-154 (5oomm), decreasing wire lengths as you go into a corner & back to longer wires once back on the straights. So masts further apart on the straights & closer together on the curves. On curves to ensure the centre line of the contact wires remain within the 2mm envelope from the inside rail edge. Tighter the radius curve the closer the masts must be positioned to maintain the contact wire within the 2mm envelope.
The image below shows contact wire on a curve within the 2mm envelope.
Peco list the following as a guide for what length wire to use on curves:
- LENGTH OF WIRE: 200mm – MINIMUM CURVE TRACK RADIUS: 803mm
- LENGTH OF WIRE: 260mm – MINIMUM CURVE TRACK RADIUS: 1355mm
- LENGTH OF WIRE: 340mm – MINIMUM CURVE TRACK RADIUS: 2315mm
- LENGTH OF WIRE: 380mm – MINIMUM CURVE TRACK RADIUS: 2891mm
- LENGTH OF WIRE: 500mm – MINIMUM CURVE TRACK RADIUS: 5003mm
Fitting the masts
For fitting catenary masts Peco do a handy tool to aid installation of masts. The part number is LC-115 Catenary Installation Jig. This tool allows correct positioning of drill holes for the masts & location of the next mast to be installed. Sold in packs of two.
One end has a hole for marking the drill hole whilst the other end has a recess which sits around the mast base. It has two raised bars which locate the tool between the rails to allow correct positioning of the mast. It also has a raised center piece which shows the center line & also acts as a anchor for the wire when marking the next mast.
Start off by selecting the position for the first mast. An example would be to begin at the start of your scenic section, or beginning from an area of point work. Every layout is different so it’s up to you to choose your start point.
Start by placing the jig tool on to the rails as shown on the right with the hole end sitting over the track side.
Using a pen / pencil make a mark through the hole.
Start off by selecting the position for the first mast. An example would be to begin at the start of your scenic section, or beginning from an area of point work. Every layout is different so it’s up to you to choose your start point.
Start by placing the jig tool on to the rails as shown on the right with the hole end sitting over the track side.
Using a pen / pencil make a mark through the hole.
Drill a suitable sized hole for the threaded part of the mast to fit through. Peco masts use a 3mm drill bit, Dapol use a 4.5mm drill bit.
Feed threaded part of the mast through the hole.
Place washer / nut onto the threaded part & tighten nut. On the Dapol mast don’t over tighten the wing nut as you’ll snap the threaded part off the mast!!
Make sure the mast & registration arm are at 90 degrees to the track.
Place the jig tool back on the track with the recess part sitting around the mast base.
Hook one end of the contact wire around the raise center pip.
At the other end of the wire place the second jig tool on to the track with the hole end facing over the trackside. Hook the other end of the contact wire over the raised centre pip.
Now as before mark the drill hole. Remove the jig tool & drill the hole then fit the mast making sure it’s at 90 degrees to the track.
Now fit the wire on to the mast registration arms making sure the level wire (contact wire) is the one that faces the track, whilst the curved catenary top wire is to the top.
Now place jig tool against the second mast & repeat marking, drilling, fitting the masts around your layout.
Curves
So as mentioned above use the longer wires with the mast further apart on the straights as seen in the photo below left. On the curves the spacing between the masts is closer & using shorter wires around the curve to maintain within 2mm from the inside rail at the center of the curve. As seen in the photo below right.
So as you can see in the photo on the right that the contact wire center line comes within the 2mm envelope on the curve center. Tighter the curve radius the closer the masts will be to keep the contact wire within the 2mm envelope. Lesser the radius curve then the further a part the masts will be.
For stations the catenary often use gantry spans or similar to allow positioning of masts further back from the platform edge & track so they don’t foul the platform. Various catenary gantry spans are available such as our mix & match range found here in our shop: https://www.scalemodelscenery.co.uk/?s=catenary&post_type=product&v=79cba1185463
However on the UK network some masts can be found nearer the platform edge, a small local station to me has this set up. This has has been replicated in the photo on the right featuring a small through station.
To fit a single mast where the platform is start by marking out the drill hole from the platform edge as shown on the right. Then drill a hole big enough to take the mast base through the platform. Then drill a smaller hole to take the threaded section of the mast.
Insert the mast & secure in place with the nut & washer below the baseboard. Fit the wire & make any adjustments to the wire & mast as needed. Then using model filler, fill in the hole around the mast & level off with the surrounding platform. Once the filler has set paint to blend in with the rest of the platform.
If your needing more info on the Peco catenary system check out Peco’s ‘Shows You How Series’ Number 26 – Modelling Overhead Catenary. Found in most good model shops or direct from Peco.
You can also see more in this video:
https://www.youtube.com/watch?v=If7pNEUrp-U
Happy Modelling
Great post Iain. I’ll be reading this again. Answered most of my questions 👍🏻
Your welcome 🙂