Sleepers
Sleepers are at the core of Calders & Grandidge’s business. We have a long tradition of providing high quality track timber for use in Britain’s rail network in both hard and soft wood and are now the leading suppliers to Network Rail.
We have proven to be at the forefront of research into alternative species and to be constantly forward thinking in our approach to the track timber market. With our own initiatives in place that look ahead and tackle the problems of tomorrow and provide workable solutions for industry, not only were we the first business to bring FSC sleepers into the UK market, but we were also the first to introduce and supply Brazilian timber to the UK when previous sources were deemed unsuitable.
At any one time we stock a full range of hard and softwood crossing timbers as well as approved hard and soft wood sleepers. With our full saw milling facilities on site we are able to produce bespoke size track timbers, for example the bevelled sleepers we supply for use in the London Underground.
All of our sleepers are treated and fitted at our site in Boston, Lincolnshire to either standard specifications or to the bespoke specifications of the individual customer. Nationwide delivery is available of sleepers ready for use.
Production Process
Inspection & Classification
Our sleepers are inspected at source shortly after the timber is harvested. Sleepers are then graded into sizes and stacked accordingly for partial seasoning.
Drying
We believe the best way to dry timber is naturally, by air. This process may take longer, but we believe it is the only way to ensure high quality timber sleepers.
Sleepers begin drying at source where they are laid out for partial seasoning. Once they have been shipped to our site in Boston, Lincolnshire they are moisture tested again and laid in graded stacks for further seasoning.
We leave six to twelve months - depending on the size of the individual sleeper - for the natural drying process to be completed. During this time sleepers are consistently moisture tested, and are not treated any further until their moisture content is below 28%.
Fabrication
Once our sleepers have reached the desired moisture content they are ready to be fabricated. At this stage we drill the holes for the chairs to be fitted into after impregnation.
Impregnation
Creosote impregnation gives your timber sleeper the longest life span possible and protection from harsh conditions. Pressure treated creosoted sleepers provide a minimum desired service life of forty years, but may last considerably longer.
Sleepers are pressure treated in one of our two 36m creosote impregnation vessels. Having these resources means we are able to get large orders treated quickly and efficiently, meaning your order gets to you faster.
After pressure treatment sleepers are again left to dry before being dispatched to support the nations rail network.
Note: Creosote impregnation is only used in softwood sleepers, hardwood sleepers are not pressure treated.
Fitting
This is the final stage in the sleepers production process. Once it has dried we machine fit the steel chairs into the previously drilled holes. It is these chairs that will grasp the rail tracks and hold them firmly in place.
Benefits of Timber Sleepers
Transportation
When in transit and during handling, sleepers are likely to bear hits and knocks, wood is better able to withstand surface damage whereas the galvanised face of a steel pole is thin and can easily be damaged leaving the steel open to the elements and causing rust.
Ease of Machining
The ease of which timber can be machined means we are able to tailor our stock range of sleepers to your individual requirements and specifications. Bespoke design is a much more costly and time consuming process when dealing with steel and concrete.
Ease of Installation and Maintenance.
Timber is a lighter material that steel or concrete, making it easier to handle. This means that the installation time and man power required is greatly reduced, saving you money. Throughout the life of your sleeper being lighter also makes it far easier to maintain and handle, should it require any attention.
Cost Saving
Wood sleepers are less expensive that steel in many areas. These include the raw material cost and transportation, and we are able to pass these savings onto you.
Furthermore timber sleepers are easier to install and modify on site, meaning you will be constantly saving money throughout the life cycle of your sleeper through reduced maintenance costs.
Environmental Impact
All the timber we use in the manufacture of our sleepers is FSC/PEFC chain of custody certified, meaning all the trees we harvest come from sustainable managed forests. No other sleeper material comes from a renewable source, making timber the only true eco-friendly source material.
After their service life, timber sleepers can be recycled to suit many other applications and are very popular as garden features; alternatively they can be used as fuel also. This adds value as well as additional years to the lifecycle of your timber sleeper.
Product Acceptance - Accepted Hardwood Timbers
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Datasheet
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