Rail Types
Railway tracks consist of two parallel steel rails, which are laid upon sleepers (or cross ties) that are embedded in ballast to form the railway track.
The rails, if doublehead or bullhead type, are secured by wooden keys into cast-iron chairs which are fastened to the wooden sleepers with screws (See photo below). Flat-bottom rails are fastened to the sleepers with rail spikes or with screws and baseplates for wooden sleepers, or Pandrol or other patent clips for steel or concrete sleepers. Fishplates are used for joining rails.
Sleepers spread the load from the rails over the ground, and also serve to hold the rails a fixed distance apart, called the gauge. Early FR track used stone block sleepers, separate blocks under each rail, which relied on the ballast to hold the rails to gauge. This was normal practice on horse-worked railways at this period but wooden cross-sleepers began to replace them in the 1840s, to provided resilience and to hold the gauge better. (Much later, concrete pot sleepers were used, sometimes with a steel tie-bar between them, as a (wartime?) economy measure on sidings on the Cambrian line and possibly other GWR routes, but have not been used on the FR.)
Reinforced concrete "pot" sleepers stored alongside the mineral line at Minffordd yard - another handy Fredtrack bargain buy?.
It is believed these came from Minffordd yard after the standard gauge sidings were removed.
Picture: Owen D. Chapman (cropped from original) April 2006
Railway tracks are normally laid on a bed of coarse stone chippings known as ballast, which combines resilience, some amount of flexibility, and good drainage. However, track can also be laid on or into concrete (slab track). Across bridges, track is often laid on sleepers across longitudinal timbers.
There are a number of types of rail, mostly of a uniform cross section.
Fish Belly
The oldest type on the FR - traces found in Boston Lodge yard in the early days of restoration. An exception to the uniform shape in that the depth of rail bows between sleepers. Usually cast-iron used elsewhere, but according to Boyd the FR ones were wrought iron.
Double Head
A symmetrical section, which in theory could be reused by inversion when the upper head became too worn. However in practice the lower edge received permanent impressions from the chairs, so that when inverted the new top surface would not give smooth running.
Some of this type survives on the FR and it is intended to restore it to the running lines through Minffordd station as a historical feature, part of the Waggon Tracks project.
Bull Head
The head is much bigger than the foot, to maximise wear life. Replaced much of the doublehead on the FR but not all. Some bullhead rail with its chairs was obtained from the Penrhyn Railway in the 1960s and was used in the reopening phase.
Flat bottom
Can be spiked down to wooden sleepers without chairs but is usually used with baseplates on wooden sleepers for recent relayings on the FR. Used on the WHR on steel sleepers with bolts or Pandrol spring clips.
Tramway type grooved rail
Used on Britannia Bridge and the other level crossings on the CTRL as it can be inset within the road surface and preserves the flangeway. It is laid on a concrete slab without separate sleepers.
