First Great Western says services running through these stations may be delayed by up to 20 minutes at short notice.
It added an estimate for the resumption of normal services will be provided as soon as it has fully assessed the problem.
Check the First Great Western site for details.
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The victim of an assault in Cippenham was flown to hospital by air ambulance this afternoon.
A rapid response vehicle, an ambulance officer, an air ambulance and an ambulance crew were all called to an address in Earls Lane at 2.10pm.