Your questions about how severe weather affects Great Northern services answered here…
The extremes of our summer weather - from high temperatures to prolonged rainfall - cause problems for the rail network such as the risk of line-side fires and buckled track.
On warm days, rails in direct sunshine can be as much as 20 degrees centigrade above air temperature. As rails are made out of steel, they expand as they heat up and are subject to strong compression which can cause the track to buckle.
If it does, the line must be closed and the track repaired before services can resume, causing considerable disruption. Usually, these repairs can't be done until the temperature of the rails has dropped.
If a section of track is judged to be at risk, we introduce local speed restrictions - slower trains exert lower forces on the track and reduce the chance of buckling.
UK train services are vulnerable to snow and icy weather conditions because they draw power from a third rail running alongside the track.
When the rails are covered with a layer of ice it can act as an insulator, making it difficult for the trains to draw power and move.
We work with Network Rail to do what we can to stop the ice forming in the first place. We run de-icer trains and 'ghost' trains (empty trains) throughout the night to try to keep the ice from forming but, despite our best efforts, ice will form in freezing temperatures and trains become 'stuck' and 'fail'.
We're guided by Network Rail, who manage the UK's railway infrastructure, about when it is safe for us to run trains on their lines.
UK train services are vulnerable to delays when thousands of tonnes of leaves fall onto the railway lines each autumn.
These leaves are compressed by passing trains, to create a thin, Teflon-like layer on the rails, so drivers have to break earlier when approaching stations and accelerate more gently to avoid wheel spin. The leaf mulch can also insulate the electrified 'third rail' that our trains draw their power from.
Network Rail works hard to cut back tree branches and plants along the trackside and has specialist vehicles to try and keep the tracks clear during autumn. However, despite their best efforts, during the period when most trees shed their leaves there will inevitably be some problems.