More than 60 trains a day were cancelled or significantly late inside a month, the latest official figures have shown.
Labour is now stepping up calls for a fare freeze for passengers as the Scottish budget is unveiled later this week.
The figures are a fresh headache for transport minister Humza Yousaf who has been under pressure to turn around performance under Dutch operator Abellio. He has already threatened to strip the firm of the franchise to run Scotland’s trains if performance deteriorates.
The latest figures show that 2,000 trains were hit by delays or cancellations between mid-October and mid-November. This is the highest figure for 2016 and a year-on-year increase from the same point in 2015.
Labour Transport spokesperson Neil Bibby said: “Performance seems to be getting worse rather than better on Scotland’s railways, so it’s no wonder passengers are fed up. They deserve a break with a freeze on all rail fares in 2017.
“Performance compared to last year is going backwards, with 65 trains a day cancelled or significantly late in the latest figures.
“These figures come after SNP Transport Minister Humza Yousaf promised improvements – instead the situation got even worse. The public deserves less spin and more substance from the minister.
“In light of these figures, it is becoming harder and harder for the SNP to say no to Labour’s plan for a fares freeze.”
The figures do not include November 17, 2016, where a broken down train in Edinburgh saw Scotland’s rail network grind to a halt. But the data does include a period when Transport Minister Humza Yousaf agreed an ‘improvement plan’ from ScotRail.
Labour will this week in Holyrood table a motion calling for cross-party support for a fares freeze in 2017. Regulated fares are due to rise by up to 1.9 per cent in January.