ScotRail pointed the finger at Network Rail as its rating fell by three percentage points to 87 per cent in an independent poll of 1,000 passengers last autumn.
The train operator pledged to improve its reliability so the “vast majority” of trains ran with the right number of carriages.
ScotRail scored better than in autumn 2012 in half of 35 areas measured by the independent National Passenger Survey.
Watchdog body Passenger Focus, which conducted the poll, said the only significant change was a six percentage points reduction in satisfaction with information at stations, to 83 per cent.
Fewer than half of passengers questioned were happy with how ScotRail dealt with delays, train toilets and car parks, although parking saw a nine percentage points improvement to 46 per cent.
The Scotsman revealed last month that transport minister Keith Brown had summoned ScotRail and Network Rail for a dressing down over their performance, which he said was unacceptable and must urgently improve.
The Office of Rail Regulation has also said train delays caused by Network Rail had got worse.
ScotRail managing director Steve Montgomery said: “Disruption affects how people feel about rail travel. While two in three delays were not of ScotRail’s making, customers rightly expect us to take the lead in delivering industry improvements. We will continue to help Network Rail reduce their track and signalling failures, as these have had the biggest impact on our services.
“For our part, we will continue to focus on improving the reliability of our trains, so that the vast majority of services are able to operate with the full complement of carriages.”
Passenger Focus said travellers simply wanted better punctuality. Manager Robert Samson said: “Passengers in Scotland want to travel on trains which arrive and depart on time.
“When their train is late, they aren’t interested in whether the blame lies with ScotRail or Network Rail. Passengers expect the industry to work together to improve punctuality and deliver the service it’s been paid to deliver.”
Mr Brown said: “While I am pleased to note ScotRail services compare favourably with the UK average and have improved in five times as many categories as the UK average, it is of course disappointing to see the slight dip in overall passengers satisfaction.
“I continue to urge First ScotRail to do better on the areas within their responsibility where scoring is down.”
A Network Rail spokesman said: “We are committed to delivering the best service we can for passengers and are investing heavily in expanding and enhancing the railway.
“Last year, Scotland saw punctuality hit a record high of 93 per cent and we are determined to continue to reduce delays as much as possible.”
The survey also showed 91 per cent of passengers were happy with cross-Border operators East Coast and Virgin Trains, both of which were down one percentage point.
CrossCountry was up two percentage points to 86 per cent satisfaction, while First Trans- Pennine Express recorded a fall of three percentage points to 85 per cent.
East Coast managing director Karen Boswell said: “The punctuality and reliability of our services remains a high priority.
“We are working closely with Network Rail to encourage continued investment in track, signals and overhead power lines.”
Customer service is way off track
The number of people seeking advice from a consumer group about trains has trebled, amid falling levels of satisfaction and added pressure on passengers caused by delays, cramped carriages and cancellations, according to new reports.
A UK survey of 30,000 passengers found that satisfaction with how train operators handled delays fell from 44 per cent to 40 per cent in the past year, although levels were as low as 23 per cent.
Total satisfaction with rail services fell from 85 per cent to 83 per cent, said Passenger Focus, adding that the lowest score was just 28 per cent for the Stansted Express route.
Satisfaction rates for punctuality was 79 per cent, down from 83 per cent a year ago, with the figure barely changing in the last five years.
Citizens Advice said in a separate report that the number of people seeking advice about trains had leapt from 14,138 in 2012 to 43,282 last year.