Network Rail has said it is reviewing a planned closure at Watford Junction which would have closed the West Coast Main line for 16 days in August.
The £81 million scheme includes renewing signalling power supplies between Kings Langley and Bushey, along with 15km of track and crossings and upgrading over line equipment.
The project was due to start to start in May, followed by the main blockade in August and then some further works over Christmas as well as in February and April 2015.
Anne-Marie Batson at Network Rail said Network Rail has been "carefully reviewing" Watford Area Renewals Programme so that it "delivers maximum value while keeping passenger disruption to a minimum".
She said: "While it is likely that limited closures over weekends and bank holidays will be required to complete the project by Easter 2015, we are aiming to deliver the improvements without a full 16 day closure of the WCML in August this year as was initially proposed.
"We are currently finalising details of the programme with our industry partners and plan to confirm details before the end of the month."