Network Rail insists it remains on track to complete the upgrade of Blackpool’s rail lines by May 2018.
The company has begun work to electrify the railway between Blackpool North and Preston.
The Department for Transport this week announced the deferral of several similar schemes around Bristol and Oxford.
But Network Rail insists there are no issues with the Blackpool project, despite documents issued by the National Audit Office suggesting its North West programme might be subject to delay.
A Network Rail spokesperson said: “We remain committed to transforming rail services across the north, increasing the number of seats, frequency of trains and improving customer experience.”
Outdated signalling will be replaced and some tracks will be realigned.