RAIL passengers in Scotland will face more expensive peak-time journeys after it was confirmed that fares are to rise by 3.1% from the start of next year.

ScotRail said the cost of the majority of trips will increase from January 2014, although off-peak fares will be frozen at current levels.

The price hike is calculated using the Retail Price Index (RPI) and is capped at the level of inflation.

Transport Minister Keith Brown had announced the pricing plans at the end of last year.

However, it had not been confirmed that they would be put in place until the RPI was confirmed.

A ScotRail spokeswoman said: "We are pleased to have frozen fares for 40% of journeys and limited others to an inflation-only increase.

"This means we continue to provide better value for money for customers in Scotland, especially when fuel and energy costs continue to rise steeply.

"We will also continue to invest. We are committed to making rail journeys more pleasant as well as delivering high levels of punctuality. This is striking a chord with customers, with nine out of ten saying they are satisfied with their rail journeys.

Scots commuters will have cheaper rail fares than those in England, where a different formula is used.

Yesterday it was announced that fares south of the Border will rise by 4.1%.

The English regulated rail-fare rise formula, based on the July inflation figures, is RPI plus 1%, while in Scotland the formula is RPI.

Train companies in England have flexibility to raise some regulated fares by as much as 5% more than the set formula, as long as the RPI plus 1% averages out among all that company's regulated fares.

This could mean that the price of some season tickets could increase by as much as 9.1% in January 2014.

However, the fact the fare rise is capped in Scotland means no regulator-fare tickets can go up by more than the RPI rate.

Off-peak fares will not be raised at all as long as inflation remains below 3.5% for the remainder of the ScotRail ­franchise, which comes to an end in March 2015.

However, passenger groups said that Scottish rail travellers were still being hit in the pocket despite enjoying lower fare increases than other parts of the UK.

David Sidebottom, passenger director of the independent watchdog Passenger Focus, said that commuters would "shrug wearily" at the news that the cost of rail travel is to rise.

He said they should demand more from train operators.

He said: "Now passengers are the main funders of the railway it is crucial that, in return for this rise, more trains arrive on time, investment in future improvements continues and the basic promises the industry make are delivered.

"It is clearly in passengers' interests that some fares are regulated. However, the way that train companies are allowed so much flexibility to set fares on ­individual routes is unfair.

"With some regulated fares going up by RPI plus one per cent some passengers could still be facing steep rises on their route. There is a need for some flexibility but not this much.

"Train companies cannot explain to an individual passenger why their fare has gone up by a certain amount. That is not transparent or fair."

SNP MSP Gordon MacDonald, who sits on the Infrastructure and Capital Investment Committee, said that Scotland was witnessing "record passenger numbers".

He said: "Passengers in ­Scotland are getting a significantly better deal than their counterparts south of the Border thanks to action by the SNP Government.

"We have recognised that, in these difficult financial times, inflation-busting fare increases are the last thing that people need.

"We have therefore acted ­­accordingly to protect passengers in Scotland."