Rail Track Maintenance
For several years around 1960 I worked for a Swiss company, MATISA, (Materielle Industrielle SA) that made and sold rail track maintenance machines around the world. These machines encompassed the very small such as portable saws for cutting rail on site to the huge, such as Ballast Cleaners which weighed in at around 50 tons.
I believe that the first specialist maintenance machines supplied to British Rail were MATISA Standard Tampers and many sidings where working MATISA tampers were stabled were known as " The Matisa siding " and these were quite numerous up and down the country. I don't know whether this is still so.
The two main machines concerned with Railway track maintenance are the Tamper and the Ballast Cleaner. Most of the work can be done with standard versions of these machines but of course there are specialised machines for maintaining non-standard track like points and crossings.
"Track description "
Rails are supported by sleepers (ties) which in turn are supported by around 12inches (300mm) depth of ballast. Quality of track is dependent upon several factors.
- The sub-stratum or foundation which supports the track system
- Quality of ballast.
- The sleepers or ties.
- The rail itself
- Rail fastenings
I am not a Civil Engineer so know little about preparing the foundation for a railway track. However, it's obvious that it must be firm and well drained
Ballast should be hard, sharp stone. Sharp means that is angular in form. Over a period of use ballast gets its sharp corners rubbed and chipped off and then will not form the solid bed for the sleeper that is necessary. Imagine trying to construct a dry stone wall from rounded stones. At long intervals, therefore, ballast has to be renewed or cleaned. This is done by huge machines which excavate the ballast, sieve it to remove the detritus and replace it, together with a top-up of new ballast under the track.
"Sleepers or Ties"
At one time these were exclusively of timber, but reinforced concrete is used now on all main lines, although examples of wooden sleepers can still be seen.
These are made from a manganese steel which is easily weldable, self-hardening with use, but reasonable to drill or saw. There are two cross-sections of rail used on train systems - bullhead and flatbottom. The bullhead rail is supported in a cast steel 'chair' and secured by wedges; the flatbottom rail rests directly on the sleeper. Bullhead rail is seldom seen now and is virtually obsolete for mainline track.
Rail sections are specified by a standards number and a weight. I believe that a typical mainline flat-bottom rail used on UK railways is BS113A - 115lb/yard or its equivalent in metric measure
Chairs used with bullhead rail are usually secured by coach bolts into wooden sleepers and the rail secured in the chairs by sprung steel wedges.
Methods of fixing flatbottom rail to sleeper vary a lot. Steel-reinforced concrete sleepers are most often used today. The rail sits on cast steel plates and there are many patented fixings. Some use screwed fittings, others employ spring clips known as 'spikes' that fit into preformed holes in the sleeper.
|Spikes were removed using 'Spikepullers' as shown in the illustration. The model shown could be fitted with a range of jaws to fit a variety of spikes, some of which are shown.|