SELLA CONTROLS have been awarded a contract from ESG Rail, who has been contracted to develop, supply, install and commission a physical prevention of overspeeding (PPOS) device for the London tram fleet. This protection system will operate independently of the other tram monitoring systems and will stop a vehicle if it is found to be travelling at excessive speed within pre-defined locations.
Transport for London (TfL) began work on the feasibility of introducing this new safety measure, which has not been introduced on any UK trams before, shortly after the tragic overturning at Sandilands, Croydon, in November 2016. It is one of the recommendations set out by the Rail Accidents Investigation Branch (RAIB) following the tragic tram overturning and is expected to be fully operational by the end of 2019.
SELLA CONTROLS will provide the equipment necessary for the PPOS system to be installed on all of London’s trams. The system consists of a PPOS controller (EKE Trainnet) fitted to each tram, together with a Tracklink III Reader. Tracklink III beacons will initially be installed at a select number of high risk areas on the routes but will have the flexibility to be introduced elsewhere on the network.
In the event of a tram over speeding in a speed restricted area, the PPOS controller will interrupt the power to the PPOS safety relay. This will result in full service brake application and will bring that vehicle to a controlled stand-still. This event will be alarmed at the London Tram control room via 3G/4G connection. SELLA CONTROLS will be providing the server and workstation for handling the alarms and storing the data. In addition SELLA CONTROLS are also responsible for providing a new Depot Wi-Fi system which will be used to download PPOS data from each tram as it enters the depot.
Mark Davis, TfL’s General Manager of London Trams, said: “We will never forget the tragedy at Sandilands and from day one have focused our attention on preventing this type of incident from ever happening again. Awarding the contract for a new automatic braking system Is a first for trams in the UK, and not only will it improve safety for customers in London, but we hope it will lead the way for other tram operators across the country. We will work hard this year to have the new system, which will automatically apply the brakes if a tram is exceeding the speed limit, in full operation by the end of this year.”