A signalling failure at Ladbroke Grove is affecting trains running to and from Paddington Station.
Engineers are at the scene on Monday (October 17) to fix the “track current failure”, say Network Rail, which has warned of expected delays until 5pm .
A Network Rail tech team has been at the site of the signal failure since 10.30am.
Delays had earlier been forecast to last until 12.30pm.
Speaking to getwestlondon at 1.10pm, a spokesman said it had caused delays totalling 944 minutes across all services.
Earlier in the day the Heathrow Connect service was suspended, with passengers advised to take the route 140 bus instead.
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