Services at one of London’s busiest train stations are being disrupted after a report of smoke on the tracks.
South Western Railway (SWR) said some of its London Waterloo services were being forced to run slower than usual while a safety inspection took place.
The firm said “smoke was reported on the track” between the station and Vauxhall.
Passengers were warned of delays on services to and from London Waterloo and Guildford, Woking, Chessington South, Dorking, Hampton Court, Shepperton and Strawberry Hill.
SWR did not say whether the incident was related to high temperatures.
The operator also issued a general alert to all passengers, stating that services across its entire network “may be revised” because of the hot weather on Tuesday.
It cancelled a number of services scheduled to run in the afternoon and early evening.
This affects journeys between London Waterloo and Weymouth via Winchester, Southampton and Bournemouth, and between London Waterloo and Aldershot via Woking and Guildford.
Some services between Exeter St Davids, Salisbury and London Waterloo will only run as far as Basingstoke.
National Rail Enquiries said Elizabeth line services between London Liverpool Street and Stratford will be disrupted on Tuesday afternoon.
Eastbound services that normally run from platform 17 at London Liverpool Street to Gidea Park have been cancelled, with passengers wanting to travel east advised to use Shenfield services from the low-level platform A.