Transport for London (TfL), which runs the capital's public transport, has extended its outsourcing arrangement with supplier CSC.
Under the new $33 million (£21 million) deal, which will run for 27 months, CSC will provide service desk and desktop support services, understood to be based on a BMC tool. The original deal began in 2007.
Around 13,000 IT users at TfL will be supported by the contract. It also covers real time passenger information for some London Underground stations.
The work is part of TfL's ongoing transformation agenda, which has so far seen a massive data centre and system consolidation programme, and an overhaul of IT efficiency, but was recently slowed down.
Early last year, the SAP-based organisation said it was delaying upgrades of its IT systems as part of efforts to cut £375 million from costs. It also moved to reduce the number of technology staff it employed.
TfL's IT suppliers range from Cubic Transportation Systems, which handles the Oyster card IT, to Easynet Global Services and Serco, which provides IT services for CCTV. It also uses the Microsoft Azure cloud computing platform to host publicly-available data feeds.
In November, TfL said it was preparing to implement a £110 million communications and control systems package for Crossrail, the rail project that will connect Heathrow Airport with the City of London and Canary Wharf.