The Epping to Chatswood rail line will be shut for months under the terms of a $3.7 billion contract signed this week for a private operator to run the adjoining north-west rail link to Rouse Hill.

New South Wales Transport Minister Gladys Berejiklian would not confirm the length of time the Epping to Chatswood line would need to be shut down, but it is understood the government is preparing to reveal how it intends to transport the tens of thousands of commuters who currently use the line.

Fairfax Media has previously reported industry speculation the line would need to be shut for between three months and six months to allow for a new signalling system and screen doors – features of the fully automated north-west rail link – to be installed.

The Epping to Chatswood line, which opened only in 2009, will be handed over to the new operator of the north-west rail link. When that line opens in early 2019, trains will run in a shuttle between Rouse Hill and Chatswood.