PASSENGERS "don't care how old their trains are", ScotRail's boss has insisted – as he admitted carriages on a new high-speed train roll-out are up to four decades old. 

Alex Hynes, managing director of ScotRail Alliance, said the public just wanted services to be comfortable and reliable, reports The Herald

And he insisted many of ScotRail's competitors would "kill" for the company's performance and customer satisfaction record. 

Mr Hynes was speaking during a fringe event on Scotland's railways at the SNP's autumn conference in Glasgow

He was accused of forgetting about services to areas such as Inverness, where the rolling stock was branded "appalling". 

The ScotRail boss said it was investing £60 million in the infrastructure of the Highland main line, as well as rolling out refurbished high-speed intercity trains. 

But under questioning from an audience member, he confirmed the carriages are "up to 40 years old". 

He added: "But there's not much left on them which is actually 40 years old. It's a bit like an airliner where you change every component. 

"They've been thoroughly refurbished. Customers don't care how old trains are, they care – is it comfortable and is it reliable."

He insisted the refurbished trains are "fantastic" and that customers will "love" them.

Earlier, he defended ScotRail's punctuality record, insisting: "ScotRail is the most punctual large operator in the UK. 

"It's not good enough and we need to work hard to make it better, but there are lots of train operating companies out there that would kill for our performance and customer satisfaction statistics."

Mr Hynes said 60 per cent of all punctuality failures were down to Scotland's ailing rail infrastructure, which is managed by Network Rail. 

He also faced questions over capacity issues on the Edinburgh to Inverness line, which one SNP delegate described as an "absolute nightmare" and bad for tourism.

The ScotRail boss said services were experiencing a boom in passenger numbers on weekends and particularly on Sundays, while the three-car diesel trains operating on the line are "simply not designed for journeys of that type". 

The Scottish Government is currently preparing a public sector bid to take over the railways.

State-owned ferry operator CalMac has confirmed it is interested in running services.