Greater Anglia announces that some trains will not stop at Stratford, with temperature in London expected to exceed 30C

There are no leaves on the track, nor the wrong kind of snow. But rail passengers seeking the Olympic Park will find many trains not stopping at Stratford on Tuesday – because it is too hot.

Greater Anglia, which runs trains from Liverpool Street to destinations east of London, announced that some services would be suspended and others would not stop at Stratford, the key station for the Olympic stadium, from midday because of the heat.

Speed restrictions will be put in place as the thermometer passes 30C, a figure long forgotten in Britain.

A Network Rail spokesman said the heat affected the workings of the remaining older overhead cables out of Liverpool Street, dating back to the 1950s, which are in the process of being replaced. He apologised for any disruption and stressed that the vast majority of services would still run to Stratford.

A Greater Anglia spokesperson said: "There are some revisions in place to our mainline timetable today between 12.00 and 19.00 as a result of speed restrictions imposed because of the hot weather forecast. We are working with Network Rail to minimise the disruption for our customers."

Nine services on the Norwich to London Liverpool Street service will not stop at Stratford, while there are also revisions and cancellations affecting some Colchester Town, Southminster, Southend Victoria and Witham services. The company said it was a small proportion of the 1,900 services it operates each day and would not affect its West Anglia route or Stansted Express service.

The disruption comes a day after the Central line, one of the two major London Underground lines connecting the centre of London to the Olympic Park, was shut down completely for two hours after a power cut.

The RMT union called for an urgent inquiry into whether cuts to staff and maintenance budgets had caused the stoppages to train and tube services, and warned that similar transport problems during the Games risked "dragging London into international laughing stock territory".

Greater Anglia said Transport for London, London Underground and its fellow train company c2c would accept their tickets on Tuesday afternoon for alternative routes to Stratford and beyond.

Passengers can be reassured temperatures are predicted to drop before the opening ceremony on Friday.