LIGHTNING is believed to struck signalling equipment which halted trains on the east coast main line between Edinburgh and Berwick today.
The incident at Reston in the Borders at 7:40am stopped East Coast and CrossCountry services for up to two hours, with disruption expected to continue until 1pm.
East Coast warned passengers to expect delays of up to one hour.
Further north on the east coast line, signalling problems also disrupted trains between Kinghorn and Kirkcaldy in Fife.
Elsewhere, signalling faults also delayed ScotRail trains between Dalwhinnie and Kingussie on the Perth-Inverness line, and continuing problems with radio signalling equipment affected trains on the Inverness to Wick and Thurso route, with buses replacing trains between Georgemas Junction and Thurso.
A Network Rail spokesman said: “Heavy rain and lightning are moving into parts of Scotland and we’re out on the network to react to any issues quickly.”
On the roads, water lying on the main cross-Border link because of heavy rain hampered drivers, with sections affected including the A74(M) between junctions 14 (Elvanfoot) and 15 (Moffat).
Motorists were also urged to take care because of surface water causing “difficult driving conditions” on the M8 through Glasgow.
Fog provided an additional hazard to drivers crossing the Forth Road Bridge.
A Transport Scotland spokesman said: “After a glorious spell of weather the Met Office is warning there could be some disruption across the network today and tomorrow as a result of heavy showers.
“While not an exact science, the Met Office believe the intensity of the rain could have an impact on many areas and motorists affected should drive according to the conditions by allowing extra time for braking and be aware of heavy surface water as well as the potential for localised flooding on roads.
“Once again, we’ve seen how quickly weather conditions can change in Scotland. We’ll do all we can to minimise travel- related disruption and would ask drivers and commuters play their part by planning journeys in advance using all the available traffic and travel information.“