Two earlier cancellations were behind the overcrowding which prompted renewed criticism of operator Abellio ScotRail and its embattled managing director Alex Hynes.
Local MSP Christine Grahame, who represents the Midlothian South, Tweeddale and Lauderdale constituency, hit out at “failures” on the Borders line during First Ministers Questions at Holyrood.
“And there was also a pregnant woman made ill.”
She added: “For Alex Hynes to claim that in committee last week that customers are already benefiting from improving service delivery, he needs to get out and about on the Borders trains to hear what my constituents think of his improvements.”
The cancellations today were as a result of a train which failed earlier this morning.
But she added: “I will re-inforce to Mr Hynes and his colleagues the critical nature of providing a service which passengers can rely on and feel safe and comfortable to use.
“Improvements across ScotRail’s services have been patchy with passengers in the east of the country continuing to be let down by ScotRail.”
Transport secretary Michael Matheson met senior figures from Abellio this week to underline the need for improvement, Ms Sturgeon added.
“I said a couple of weeks ago in this chamber that ScotRail is in the last chance saloon and I repeat that today. They must meet the commitment contained in the performance remedial agreement that that have now signed up to.”
The Scottish Government issued Scotrail with a remedial notice at the end of last year and operator pledged to improve performance.