Scottish rail passengers are being reminded to expect travel disruption as upgrade works begin.

On Saturday, a revised timetable started which will last until mid-December.

Trains may be diverted, cancelled, less frequent or have replacement buses as part of the journey while the engineering works are ongoing.

Journey times will be longer and queuing systems will be in place at key stations.

The works will mainly take place after the evening rush hour and over weekends.

A special "football service" will run to help people travelling from the Aberdeen area to the Betfred Cup semi final at Hampden on Saturday.

There will be similar arrangements for those going to the autumn rugby internationals at Murrayfield.

Jacqueline Taggart, ScotRail Alliance customer experience director, said: "We are going through a massive period of change on Scotland's railway. The work that we are carrying out over the next few months will bring about a revolution in rail - with more and better trains, more services and more seats than ever before.

"However, while we transform the railway, there is inevitably going to be some impact on people's services.

"We are doing everything we can to minimise this, and to keep people moving."

Ms Taggart added: "No-one likes having their journey changed. However, this short term disruption will lead to a more reliable, better rail network that will rank amongst the very best."

An interactive timetable has been put together to help passengers plan their journeys.