Our ref: FOI-1926-2425
Thank you for your request received by Transport for London (TfL) on 16 September 2024 asking for information about the new DLR Rolling Stock.
Your request has been considered under the requirements of the Freedom of Information Act 2000 Regulations and our information access policy.
I can confirm that we do hold the information you require. You asked:
- What were complex challenges encountered during the testing of the new rolling stock that delayed the rollout
We identified issues relating to the integration between the train and signalling systems and how these behave in conditions of poor railhead adhesion. The engineers have developed a plan to overcome these issues. However, while doing this, they have identified a preexisting technical issue within the legacy signalling system which has resulted in speed restrictions being introduced in some sections across the DLR network.
Work is underway to optimise these speed restrictions, which will hopefully minimise the impact to customers on the DLR network. As a result of the legacy signalling issue, further detailed analysis is also required for the new trains, alongside existing software modifications. This has meant the new DLR trains will not be able to be introduced this year. We do now have a solution for the new trains to enter passenger service, but the initial programme is currently being stress-tested and optimised.
- What was the cost associated with this delay? Was this cost incurred by the taxpayer?
Any cost or other impacts associated with this delay have yet to be assessed.
- What mitigations or sanctions have been put into place to address this?
A series of modifications to the train and signalling have been, or are in the process, of being implemented to address this issue.
If you are not satisfied with this response please see the attached information sheet for details of your right to appeal.
Yours sincerely,
Tahsin Prima
FOI Case Officer
General Counsel
Transport for London
