Rail weld

From Festipedia, hosted by the FR Heritage Group

Rail welds are a way of joining rails without the weakness of a rail joint.

There are three main kinds of welds:

  • thermit; done on site.
  • electric arc; mostly done at a depot.
  • gas welds, on site or at depot.

The FR adopted thermit welding from February 1966. [1] Prior to this rails were welded in the erecting shop but length was limited to 60 feet because longer rails could not be taken around the line's curves on the rail bolsters.[2] A representative of the thermit welding supplier spent three days training members of the PW gang and specially made moulds to fit FR rails sufficient for fifty joints were purchased. It was at first mainly used at places where rail joint maintenance was difficult such as Penrhyn Crossing (192 ft lengths, March 1966), or where softness of the trackbed required more than a fair share of time for maintenance such as Rhiw Goch 100 mph straight (May 1966) and Garnedd Tunnel (early 1968) because of difficult access. A small brick building in Minffordd Yard (Minffordd Brick Built Store) was used to securely and safely store the thermit welding supplies and was correspondingly labelled on the door. In 2014/5 this thermit welding store was converted into warm storage for tins of paint. (Wilson, 2016) See this web site for details of the process of thermit welding: https://en.wikipedia.org/wiki/Exothermic_welding

The rails to be joined by welding may be of different sizes. It is difficult to join rails of different size by thermit welding unless specialist moulds are made. On the FR, closure rails made from rails of different profiles were usually welded up at Boston Lodge - presumably by gas. Sometimes a contractor is used and does the work on site - for example at the relaid Porthmadog layout in early 2014.


See also[edit]


  1. ^ Ffestiniog Railway Magazine, Issue 032, page(s): 006
  2. ^ Ffestiniog Railway Magazine, Issue 032, page(s): 006

Wlison H R W (2016) Report of the Trustees Y/E 30th September 2015, Society Chairman's Report, FfRS Annual Report page 9.