The Federal Group says the cost of topping up a compulsory maintenance fund for the West Coast Wilderness railway played no role in its decision to abandon the tourist attraction.

It has been revealed a so-called "sinking fund' to cover non-routine upgrades was set up as part of the Federal Group's 20 year lease of the railway.

The Infrastructure Department says the company was only required to start contributing to the fund halfway through the lease, starting payments a few years ago.

Daniel Hanna from the Federal Group says the cost of the fund did not weigh on the company's finances.

"In the tens of thousands of dollars each year," he said.

The company is blaming low passenger numbers and impending capital costs for its decision to stop running the railway in April.

It says there is only about $160,000 left in the fund.