Ballast

Ballast is a vital component of the permanent way.

The 1965 edition of the FR volunteer's Manual contains the following:

"Above the formation comes the ballast. Unlike the formation the ballast should be resilient, and in order to drain the track efficiently, porous. The ideal ballast is a small graded stone, spent ballast from British Railways is now being used, whilst ash can also be used but is not suitable as it crushes into dust and becomes non-porous. A point often overlooked by the layman is that ballast should go down below the underside of the sleeper, and indeed it is here that it is most important. Virtually all the resistance to lateral movement of the track comes from the friction between the underside of the sleepers and the ballast. By packing additional ballast under sleepers deficiencies in cross level and gradient can be rectified."

The earliest ballast used on the FR was probably Hamburg Ballast obtained from sailing ships calling at Portmadoc for slate. This is indeed the origin of the term for railway ballast since most early railways connected collieries or quarries to ports. In order to sail safety while unloaded sailing ships had to take on board a certain amount of heavy material as ballast, usually shingle or small stone. This was then available for free for the use of the railways which led to the ports.

This source of ballast for the FR must have disappeared by the 1920s but perhaps little new ballast was purchased in the 1920s to 40s.

When the railway reopened there was little money to spend on ballast. There were examples of well wishers purchasing ballast as a gift for the railway to finish re-sleepering jobs. As the railway's finances began to improve it (as recorded above) began to purchase spent ballast from British Railways. This was of very variable quality and could have a lot of soil and dirt mixed up in it. It was delivered in wagons by BR to Minffordd yard where the unloading took place at the coal hole - the standard gauge siding being high above the two FR sidings ,on top of a retaining wall. From here the spent ballast was shoveled onto a shoot. The shoot had a screen through which it was intended the dirt would fall into a spoil wagon on the first FR line. The larger ballast stones were intended to proceed over the screen into the FR ballast wagon on the second line. This arrangement did not work very well.

Of course spent BR ballast was potentially contaminated with the products of on train toilets. Platelayers were probably aware of it. However the 1965 Volunteers' Manual was silent on the subject. In fact recent and earlier research showed that the level of hazard was low. (RS&SB) The thought of it might spoil the flavour of your sandwich lunch. Once new ballast came into use this worry disappeared as all FR on train toilets have been of the contained type and emptied at Harbour Station.

When the Army relaid the section of track above Tan y Bwlch in 1965 they purchased their own new granite ballast from a local quarry. Once the PW gang saw the effect of this new ballast much more was purchased for the relaying to Dduallt and subsequently beyond. For a time ballast was purchased from Arenig Quarry but since that closed in the1980s Minffordd Quarry has been the source.

A variant of this ballast was tunnel ballast produced during the boring of the New Moelwyn Tunnel. It was graded in a plant at Tunnel South but it was larger sized stones than is ideal and was not a success.

See also

• Ballast Wagons

References

Rail Safety and Standards Board (undated) leaflet: Discharge of toilet waste from trains onto the track (T051).