ALMOST one in five railway stations across the country caters for fewer than 100 passengers a day.
A study from the National Transport Authority (NTA) says 31 of the country's 147 stations generate fewer than 100 journeys, and that more than a dozen more cater for fewer than 200.
The National Rail Census, which counted passengers at each station across the country, also shows that the €110m Galway-Limerick service is carrying fewer than 1,000 people a day.
The line, which opened in 2010, carries low numbers in part because it takes 30 minutes longer to travel between both cities by rail than by road, but there has also been criticism about a lack of services.
The annual census, which was extended to the entire network this year, is a snapshot of daily demand across the 2,400km rail network. It was conducted on November 15, 2012 and the figures have been put together over the past year.
It shows the extent of the challenge facing Iarnrod Eireann to improve passenger numbers on little-used lines, and to grow traffic on busy routes.
Chief executive David Franks has previously said he will not operate services on loss-making routes as the company seeks to cut costs, and that the Government will have to subsidise passenger services which do not make money and have low numbers.
But the census shows that even the busiest routes are running below capacity.
The most heavily loaded train was the 8am DART service between Greystones and Malahide, which carried 906 passengers at peak -- just 65pc of the 1,400 capacity. The 7.55am from Maynooth to Bray carried 850 passengers, again 66pc of the 1,280 capacity.
The number of carriages on some DART trains have been reduced in recent months in part because they were running below capacity. Trains at off-peak times are now operating with as few as two carriages as the company hopes to save €3.2 million in annual fuel and maintenance costs.
The census showed, conversely, that the 5.45am from Sligo to Connolly carried 435 people at one point -- despite capacity of 406, meaning not all passengers could secure a seat.
The NTA said the data was collected to help plan services and reflect customer travelling and commuting patterns.
"The data gathered helps guide our investment and service planning decisions, in that they are evidence-based," a spokeswoman said.
"We are doing a big exercise on timetables and such information is vital to this process. We can analyse this data, in conjunction with other large datasets such as the Census, to help understand trend patterns over the years."
Unsurprisingly, the vast bulk of railway journeys are made in the Greater Dublin Area which includes commuter services from Kildare, the north east and DART.
But, unlike most Dublin stations, Heuston caters primarily for inter-city traffic between the capital and Kildare, Waterford, Galway, Cork, Limerick, Kerry and Westport. "In contrast to the rest of the network, the highest number of boardings on the Heuston lines in the morning occurred between 7am-8am, rather than between 8am-9am," it says.
"This earlier peak is driven largely by the number of passengers . . . on early morning trains bound for other parts of the country. Intercity rather than commuter demand accounts for the majority of the market at Heuston."
The Cork commuter service has a "notably lower level of demand" by comparison with the capital, which reflects the lower population and less economic activity.
In general, intercity services across all lines carry between 300 and 400 passengers, with lower levels on trains from Heuston compared with other lines. The least-used line is between Waterford-Limerick Junction, which serviced just 156 passengers.
Fewer than 1,000 people a day make the journey between Dublin and Belfast, most of which are likely to be day trips.