Smooth tracks through leaves increasingly successfully tackled

We speak with Martijn Gerth, contract manager for asset management technology at ProRail, and solution architect Dirk Jekkers from ICT InTraffic. Together with NS, they ensured that there was little to no disruption from leaves or other debris on the tracks last season. "At least, we tried to reduce the impact of slipperiness on the tracks," Gerth clarifies. The contract partners will work together on one more campaign in 2025, after which the software and hardware will be transferred to ProRail. Therefore, Martijn Gerth is highly invested in perfecting the system, so that ProRail can rely on it for years to come.

What is the goal of the Sandite software project and what does it mean exactly?

Gerth: "The Sandite project focuses on addressing problems caused by leaf fall and other debris on the tracks. These issues prevent proper contact between the train and the rails, leading to detection loss and wheel slip. Sandite is a solution that works well. It is a special compound, mainly consisting of iron, potato starch, and binders, which is applied to the rail. This improves the contact between the wheels and the rails. So, working with Sandite is not primarily a safety measure. That's a side benefit: due to the complexity of the tracks, we have to make choices about which (slipperiest) sections can be addressed. For ProRail and NS, Sandite is mainly a punctuality measure."

Jekkers: "Sandite has been used on the tracks for more than twenty years, but managing the campaign could be much easier, and the application of the gel could be a lot more precise. Our task was to renew the software and hardware so that these aspects of the Sandite campaign would significantly improve. My role as a solution architect was to translate all of ProRail's requirements into a new software solution. We did this together with our team in Bulgaria, ICT Strypes. Since the updated software was implemented in 2023, we've already had two successful campaigns."

You’ve mentioned Bulgaria. Part of the work was done there through 'nearshoring.' What did that add?

Jekkers: "Besides the fact that there are excellent IT architects and developers in Bulgaria, it’s also about the scarcity of IT professionals in the Netherlands. In Bulgaria, we have the capacity to take on new projects and do so at an attractive rate. So, it’s a win-win situation. However, for an IT project to succeed, there is more involved than just software development capacity. You also need to understand the customer’s situation and be able to advise them on the best solution direction. This is where ICT InTraffic brings in its domain knowledge and experience. Since we are close to our customers, we can act quickly and bridge the distance that might be felt with remote teams."

What are the biggest changes in the new software?

Jekkers: "The new software uses advanced GPS technology for accurate positioning and a network that divides the track into geofences. This allows us to know exactly which track the train is on, and we can precisely determine where Sandite should be applied, and where it shouldn't. For example, switches must be excluded from treatment, which can now be enforced at the track level."

Gerth: "That's correct. The accuracy has greatly improved. Previously, the pump would be turned off when the train was within a 40-meter radius of a switch. This meant that on station yards, all adjacent tracks would be excluded from treatment, precisely where the slipperiness prevention is most important. Now, we can determine exactly when the pump should be on or off. This means less waste of the substance and better results in the areas where it's really needed."

How is it determined which sections of track will receive Sandite, and how is it applied?

Gerth: "Together with NS, we look at sections where there have been many reports of detection loss or wheel slip. The track is treated with Sandite using eight SLTs (Sprinter Light Trains), which are equipped with a pump system and reservoir. These trains are scheduled in fixed routes so that the sections to be treated are covered every day. We also need to consider the length of the line and the proximity to maintenance locations to ensure the tanks are refilled regularly."

Jekkers: "When a Sandite train enters a geofence that needs to be treated, the pump will be activated with a certain frequency depending on the train's speed. If the speed is too high, or if the area has already been treated in an earlier pass, the pump will not be activated."

Gerth adds: "All of this happens during regular service schedules. Since Sandite doesn't stay on the rails for long, applying it at night wouldn't have much effect for the morning rush hour, and that's really what matters. The NS colleagues make sure that the Sandite trains operate according to their planned schedule, so we can treat the correct sections at the planned time."

How has the new software and hardware performed so far?

Gerth: "Very well! The accuracy and user-friendliness have improved enormously. Setting up treatment scenarios has been greatly simplified, and the dashboard provides real-time insight into the status of the trains and Sandite usage. This allows us to make adjustments during operations if a train is not following its planned route. We did encounter a few teething problems during the first campaign, but they were quickly resolved. Fortunately, I hardly had to spend any time on software issues."

Jekkers: "That's good to hear. This is really what it's all about: a satisfied customer. The software was developed in a relatively short period, but despite that, we paid a lot of attention to testing the entire system. In the office, we tested it against a setup that simulates the behavior of the pump. After that, we went out a few times with the NS Train Test Center with a Sandite train to test the system in real conditions."

What are the prospects for the Sandite project?

Gerth: "We will continue to evaluate and optimize the project. With the current technology, we can work accurately and tackle problems better. I expect that Sandite will remain an important part of our track maintenance, especially during autumn. I find that the system works well. Of course, there are always some wishes, but those are more 'nice-to-haves' than truly crucial matters. As it stands, it works well."

Jekkers: "We have one more campaign to go before we hand the system over to ProRail, so we're looking at further innovations or improvements, such as being able to make adjustments more quickly in case of unexpectedly bad weather. The goal remains to minimize the impact of leaf fall and other debris on the tracks as much as possible, and to give ProRail a system that provides complete insight and control over the execution of the campaign."