The number of Transport for London staff paid in excess of £100,000 has risen by more than a tenth this year.
TfL’s draft annual report showed that 326 of its employees, plus 40 at its subsidiary Crossrail, claimed six-figure remuneration packages in 2013/14.
It said this was due to a high volume of work modernising the London Underground and building the mammoth Crossrail scheme.
This work required highly specialist engineers as well as costly overtime from existing employees, TfL said.
The report added that £188M was shaved off the cost of transport improvement works by TfL’s efficiency programme.
London Underground carried a record 1.26bn passengers in 2013/14, a third more than a decade earlier.
The bus network was at its most used since the 1950s, while the Docklands Light Railway and London Overground also saw numbers soar.
Mayor of London Boris Johnson said: “Over the past year TfL has carried a staggering number of customers on our Tube, trains and buses.
“We’ve also seen record numbers travelling on the River Thames, and the Barclays Cycle Hire scheme has surpassed 30M hires.
“A relentless focus on efficiency meant that we were able to freeze fares in real terms, while carrying on with the vital job of modernisation.”
The draft annual report will be considered at the TfL board meeting on 3 July.