The train accident in the small Bavarian town Bad Aibling was devastating. On the 9th of 2016 two trains collided directly. Twelve passengers died, 89 were severely injured. Human failure caused the accident. The responsible dispatcher at the signaling center gave the wrong instructions to the two trains. Usually there are strict safety procedures to prevent collisions and accidents. For example, trains keep distance in so called safe blocks. But usually trains deviate from schedule and the alterations have to be accommodated immediately by live dispatching. Can blockchain technology help here?
Dispatching and safety protocols are complex. Basically, every country has its own railway operations frameworks. It would make sense to standardize such frameworks. But dispatching is very complex. Because every nation has its own standards, it would be very difficult and expensive to develop a common framework which is used by all. At the moment, especially in Europe, you can find a patchwork of many different frameworks and safety protocols, especially in cross-border regions. Railway traffic is managed through control centers. But is there a better way to do it?
Distributed Ledger Technology For Railway Control Systems
How cool would it be, if trains would not be controlled by a dispatcher, but by themselves or the train operator? That would mean, a train would be self-aware. It could stop automatically to maintain the necessary distance to another train in front. In a preprint paper with the title “Are Smart Contracts and Blockchains Suitable for Decentralized Railway Control?” the authors Michael Kuperberg, Daniel Kindler and Sabina Jeschke explain how a self-activated emergency stop can be realized:
“Likewise, we assume that the trainside safety aspects of the (automated or human-operated) train operation are maintained. However, the information they rely upon are not provided by the centralized control center, but rather by the blockchain-based network.”
How can trains be active parts of the railway control system themselves? This is possible through an infrastructure built on Distributed Ledger Technology. Instead of a network of control centers this infrastructure is based on technical decentralization, which means multiple nodes.
“The blockchain identity of the train is the actor which orders paths (i.e. performs reservations of an infrastructure element for a given timeframe); it interacts with the blockchain identity of the infrastructure element via the smart contract which is the gatekeeper (ensuring consistency and a safe global state).” If you want to have a closer look at the architecture of this decentralized railway control system, take a look here.
The Byzantine Generals Problem
But what about safety? Usually, when we enter a car, we trust the driver to be aware of the traffic in front of him. In a train, the operator is in contact with the control center like a pilot in plane. Although a train operator may not talk to dispatchers so often, when it comes so safety there are strict rules of authority. Now, a decentralized network can be unstable or produce failures. Here, the Byzantine Generals problem is often mentioned. This term describes a situation in which decision-making elements of a distributed computer system must come to an agreement, but one or some parts act unreliable or not in the interest of the system as a whole.
In their preprint Michael Kuperberg, Daniel Kindler and Sabina Jeschke write:
“At the same time, large-scale networks with decentralized decision-making have appeared and maintained operation, e.g. the public Bitcoin and the public Ethereum blockchains. Such networks succeed in horizontal scaling, a working set of rules for consensus (which is a systematic decision-making using defined majority rules), and in fault tolerance. At the same time, achieving suitable QoS and performance (latency, throughput, predictability) while maintaining scalability remains challenging in decentralized DLTs and blockchains. Ultimately, our solution architecture is technically suitable for both logically centralized and logically decentralized setups: since we use a private-consortial(non-public)blockchain as the “engine” to run our algorithms and store our data, additional nodes can be added and additional parties can be onboarded.”
Window Of Opportunity For New Business Model
The decentralized approach of railway operations has another decisive advantage. It may open up business opportunities. The research of decentralization in railway control shows how autonomous vehicles can pay for the usage of infrastructure on their own in an unsupervised manner. With cars and cargo vehicles who might have to pay tolls or parking fees this is not possible, yet.
“While there are proofs-of-concepts16 and interest groups with the focus of car-to-infrastructure payments, they are neither targeting ahead-of-time reservations nor do they cover limited-access, restricted-capacity infrastructure that is the cornerstone of railway operations. Our approach includes the enablement of trains to establish trade relationships with each other, e.g. to enable unsupervised monetary compensation from a delayed express train to a freight train when the latter yields its priority so that the express train can reduce its delay.”
For this vision research is concentrated on peer-to peer communication between trains and machine-to-machine payments.
Conclusion
What we have learned:
- Blockchain technology can make railway control systems safer
- It can make dispatch more efficient
- It can keep track of maintenance and repairs of the infrastructure. The state of the signals and paths is monitored and failures can be detected faster. A huge number of train delays come from defect signals. So in the end, blockchain technology can contribute to the goal that more trains arrive on time
- Distributed Ledger Technology can open up new business models in the field of vehicle-to-infrastructure payments
This was the first article from the series blockchain applications in real life.
