Rail renewal
Using digital technologies to improve rail infrastructure
In it for the long haul
Skerne Bridge in Darlington, England has been used by trains for almost 200 years. According to the UK’s National Rail, it was the world’s first public railway to use steam locomotives, making it the birthplace of today’s modern passenger railway.
The lifecycle of railway hardware is a major challenge. We ask a lot of it. Aging infrastructure, like rail tracks and the structures that bear them must last decades (or centuries, in some cases).
The sheer costs and logistical challenges mean that we can’t simply replace infrastructure every few years just because a better version is now available, as we might a smartphone. Outside of the natural renewal cycle, we need to look at doing more with what we have.
That means squeezing as much longevity out of it as possible. Doing so can mean extending the life of tracks. But it is also about improving efficiency, safety and the passenger experience, and by providing increased operational flexibility - for example, making cross-border operations easier.
Some of the network is much older than the people who operate or travel on it. Rail operators want to replace old mechanical rail systems with modern digital alternatives.
The idea of a digital rail network is to create a digital model where we can run simulated trains on simulated tracks, so we can quickly test new trains, subsystems and autonomous driving in the ‘real world’, and work out the best way to optimize routes. It also aims to provide a real time model of the network in which we have an overview of where everything is all the time and can make real time interventions to improve operations.
Digitizing the track
To create a virtual network, we first need to digitize rail infrastructure, and do that efficiently and cost- effectively.
Much of today’s route data is currently based on manual observation and record taking, making updates slow. Digitization could markedly improve things, but building a digital model of rail routes means painstakingly gathering data on every slope, curve, signal location, crossing, local wildlife habitat, and so on.
This can be done through a range of new technologies implemented onto signals and tracks. However, this is rarely as simple as plugging in some sensors. What will this take?
This requires sensors (not necessarily on the train itself) to collect this data at scale. LIDAR (with a lot of processing power behind it) is one common option today, but a range of automatic data collection technologies are also suitable, for example, accelerometer data taken from trains or image recognition via conventional optical cameras. To this end, UAVs are also starting to show promise as a cost-effective way to quickly access and assess infrastructure - being both increasingly economical and highly mobile.
In addition to sensing, this digitization will require Geographic Information System (GIS) technology that combines sensor data with other sources, such as satellite images, to create real-time topology maps. Success will largely depend upon how closely the digital replica adheres to the real network it represents.
That mapping will allow models to be created of the network that support optimal decisions about network changes, like exactly when to replace track components based on real time data on track status, and when to schedule upgrades to minimize disruption. It also enables future decisions – such as increased train capacity or opening new lines – to be simulated to understand their implications on the network.
As ever, these things are not simple. As well as deploying sensors and collecting new data, there is also a vast amount of legacy data, often collected in inconsistent formats (from multiple database types, to Excel, to paper records). A rail digitization project will need to reckon with this, through data discovery, cleaning, and centralization of all data, backed by robust data governance and cloud-based database management tools.
Digitizing the signals
This is the process of ensuring that every signal – some of which are still purely mechanical – is electrified and connected and can be observed and controlled from a central system. Digital signals bring many benefits, allowing for more optimal route management.
An example of utilizing signals to deliver value is the US’s Positive Train Control (PTC), which can automatically stop or slow trains where there is a risk of collision, derailment, unauthorized movement, or passing through switches left in the wrong position. PTC uses on-board GPS and data communication systems that relay information between trains, signal and trackside sensors, and railroad back offices – allowing remote monitoring. The European Rail Traffic Management System (ERTMS) - more on this later - is preparing the ground for something similar in Europe, through a standardized pan- European approach that will work across borders.
Digital signals can also help underpin Virtual Block Signaling (VBS), a promising approach that allows trains to be controlled and monitored digitally. Rather than dividing the track into blocks, regulated by signals, where only one train is allowed, virtual blocks move with the train defined by its longest stopping distance at its current speed. That allows more trains to be safely put onto tracks.
Ultimately, digitalized signaling systems could eventually evolve into non-physical, in-cab signaling. This already exists on some high- speed lines today, because, for example, physical signals can be difficult to read at hundreds of kph.
Once all signals are in-cab, we can envision a faster progression to fully automatic train operation (ATO) on more lines. Such systems require seamless connectivity both on the train and on the track. In Europe, further work is being done on ATO-enabling technologies, like train-to-train communication.
The eventual aim is Grade of Automation 4 (GoA4) - the highest level, in which the train is unattended (controlled without any staff on board). There are several metro lines in various countries already operating at this level, and the eventual aim would be to deploy this on a larger scale, and on other types of line.
Benefits of digital signals
Optimized route planning: Detailed information of where everything is, all the time, allows optimal route planning using sophisticated algorithms.
Dynamic route management: Dynamically adjust train speeds or routes based on traffic conditions, track work, and other factors, reducing delays and increasing overall throughput.
Enhanced safety: Digital signals improve the accuracy of train control systems, reducing the risk of collisions and derailments.
Increased efficiency: Real-time data monitoring enables more trains to run on the same tracks without delays, increasing network capacity.
Better passenger experiences: Providing passengers with real-time information about schedules, delays, and platform changes.
The challenges of signal connectivity
However, digitizing whole networks of signals, spread across nationwide networks of rail tracks – much of it in remote places – is tricky. Moving from physical to virtual signals means relying completely on radio communication systems between trains, and between trains and the wayside.
In Europe, though less so in North America, the main blocker right now is the lack of good communication infrastructure. Most current rail connectivity was built with 30-year-old 2G technologies.
As such, many railways are looking to move to 5G, under the new FRMCS standard, which is due to be implemented fully circa 2035 (though that date is flexible). That should provide the level of connectivity required for reliable networks of digital signals, and all the services that can be built on top of them.
This is coming, but it is a technically complex upgrade, involving the deployment of new 5G technologies and architectures. Rail also presents some unique challenges to rolling out a communications network, such as mapping different communications technologies to a geographically vast physical network, and ensuring security is adequate throughout.
Innovation in digital signaling is also hampered by an excess of standards - meaning each country has a different way of doing things, making innovation harder to do at scale. To solve this in Europe, the ERTMS was developed to overlay or replace existing national systems and also includes a standardized digital communication system (FRMCS) between the trains and the control centers.
That should speed innovation by allowing rail operators to learn from cutting- edge projects in other regions, and by boosting supply chain innovation by allowing companies that currently operate nationally to develop solutions for operators across the EU. If you'd like to learn more, read our FRMCS whitepaper [3].
