A signalling fault is causing major disruption to rail services in the Central Belt this rush hour.
ScotRail said the fault, which occured between the Yoker and Bowling line, is now fixed and lines have reopened between Glasgow Central and Dalmuir.
But the operator added services may be delayed, cancelled or revised until 21:00 on Wednesday, confirming 84 services had been affected.
ScotRail also said no services are currently running on the following routes:
Glasgow to Balloch
Glasgow to Helensburgh
Glasgow to Milngavie
Glasgow to Motherwell via Rutherglen
A limited service will run on the Glasgow to Edinburgh via Airdrie route.
Services via Glasgow Queen St Low Level and Glsagow Central are also subject to severe subjection.
Passengers can use their ScotRail train tickets and Smartcards on bus services, Glasgow Subway, First Scotland East buses and First Glasgow buses.
Meanwhile, drivers in and around Glasgow city centre are facing delays and congestion as the European Championships cycling time trials take place in Glasgow.
A number of significant road closures are in place, including around junction 15 of the M8 until late on Wednesday.
Celtic fans travelling to the club’s European Champions League qualifying match at Celtic Park are also being advised to allow extra time for their journeys.