An MSP has said rail passengers are being treated "like cattle" when travelling to the Edinburgh Festival.
Colin Smyth, who represents the south of Scotland, said he had received numerous complaints about services between Lockerbie and the capital.
He said he was "furious" extra carriages had not been added despite an increase in customer demand.
TransPennine Express said it planned to introduce extra capacity and hoped to improve the customer experience.
Mr Smyth said some passengers had even booked tickets for carriages that turned out not to be part of the train when it reached Lockerbie.
He said: "I often receive complaints about services to and from Lockerbie, especially overcrowding, but the number has increased significantly during the festival.
"It is astonishing that TransPennine Express haven't increased the number of carriages on services to and from Edinburgh during the festival.
"It isn't as if they didn't know about the festival."
He added that more services were needed to deal with overcrowding all year round and has written to UK government ministers urging them to intervene.
A spokesperson for the company said: "We know that our services, particularly at peak times can be very busy, and we will be introducing extra capacity across our network.
"We're also introducing more services, from December 2017 we plan to introduce additional weekday evening, and additional Sunday services that will call at Lockerbie."
The company said it had committed to delivering more than £500m of investment in the next three years including the introduction of 220 brand new carriages which would provide 13 million more seats each year for customers.
"This will lead to an 80% rise in seats at the busiest times of day which, along with the recent introduction of our free Wi-Fi and on-board media server, we hope will improve the quality of our customer's experience," the spokesperson added.