Steward Smartrak

Steward Smartrak was a proprietary, non-track-based signalling system originally developed by Steward Transport Systems, later the Helios Rail Group Technologies Division. The system used rotary encoders on wheels calibrated by trackside beacons, and trains would communicate via radio to a centralised control system that would determine the position of trains and enforce safety rules by actively sending shutdown commands during a violation.

Deployment

First trialled on the Metropolitan line in the 2020s to replace old mechanical interlocking systems at Harrow-on-the-Hill, the system was seen as an ideal choice due to its ability to modernise existing lines without needing to connect with or replace any of the existing signalling infrastructure; it could simply be abandoned in place. Helios became the most competitive bidder for the replacement contract, securing its lock-in over the system; it was later contracted to modernise much of the Underground signalling infrastructure with Smartrak.

Legacy

After the London Revolution, Helios stopped maintaining all Smartrak systems, causing the Harrow Crisis in the 2080s, where the Metropolitan line was forced to halt operations due to a failure of the system’s central computer. This forced the government to later initiate efforts to replace all Smartrak systems in the country with domestic, open-source alternatives.