Railways simply explained
The sand spreader
20. 09. 2023
Hardly anyone knows it, and yet it is essential for a "smooth" train journey: the sand spreader.
Railways simply explained
20. 09. 2023
Hardly anyone knows it, and yet it is essential for a "smooth" train journey: the sand spreader.
The sand spreader plays an important role in functioning rail traffic. Various influences, such as rain, snow or ice, reduce the friction between wheel and rail - the risk of the wheels skidding or even locking increases significantly. So that this does not happen, the sand spreader with all its components are used to prevent this from happening.
But what exactly does the sand spreader do? As his name says - he scatters sand! The sharp-edged sand, which is blown under the wheels onto the rails through the sandfall pipes increases the friction between wheel and rail. This prevents the wheels from spinning or locking in difficult weather conditions. The sand spreader thus ensures that the power of the locomotive is actually transferred to the track. But the sandy helper is also used when braking processes and prevents the wheels from slipping or "gliding".
The sand is stored in separate storage containers, usually in the front part of the train. Metering mechanisms regulate the amount of sand to be spread. The sand drop pipes lead from the storage container to the spreading units, which are designed to distribute the sand evenly on the rails. This enables the sand spreader to run smoothly.
The question remains, how much sand goes through the spreader on average? That is difficult to answer in general terms and depends on many factors, such as the weather and the condition of the rails, the route, the weight of the train or the operation. In short: depending on whether the rails are dry or damp, steep or flat, or perhaps even covered with leaves depending on the season, more or less sand is needed for the journey.
The sand spreader is operated from the driver's cab of the railway vehicle. In modern traction units - such as the Taurus locomotive - sanding is done with compressed air and at the push of a button. The responsibility lies with the driver, who operates the sand spreader and uses it in a targeted manner to improve traction in demanding situations. The Taurus locomotive has four sand boxes, each with a capacity of 100kg of sand. An electric heater in the hopper ensures that the sand remains dry and ready for spreading. In addition, compressed air and air circulation ensure that the sand does not overheat or damage the heating cartridges.
An unknown employee of the Camden and Amboy Railroad (C&A) laid the foundation for the sand spreader as we know it today: In 1836, New Jersey was hit by a plague of locusts. The infestation was so dense that the safety of train operations could no longer be guaranteed. At the time, the C&A employed its own staff to sweep the rails clear, but this proved to be only marginally effective. Even brushes and scrapers did not have the desired effect. An employee who is still unknown today began to experiment with fine sand. In the beginning, this was done by hand on the tracks in front of the locomotive, but a short time later the sand spreader was created. This not only solved the plague of locusts, but its function is still irreplaceable almost 200 years later.