The company says only around half of Britain's rail network will be open on strike days with a very limited service running on lines.
Network Rail has warned that the three-day train strike next week will cause six days of disruption to services.
More than 40,000 staff at Network Rail and 13 train operators are expected to walk out next week on Tuesday 21, Thursday 23 and Saturday 25 June in a dispute over pay and redundancies.
Network Rail said the six days of disruption are due to the impact on services on the days in between the strikes.
The company said on lines that are open, services will operate from 7.30am to 6.30pm only and not all stations will be served.
It has advised passengers "who must travel" to "plan ahead" to ensure they can complete their journeys within this window. Rail strikes 'entirely pointless' - Transport Sec Transport Secretary Grant Shapps told the Commons the proposed rail strikes are "entirely pointless" and "counterproductive" because the pay freeze for rail staff was "coming to an end".
"These are entirely pointless, counterproductive strikes. They should never have been called and the party opposite should recognise that fact," the transport secretary told MPs.
Earlier in his speech, Mr Shapps said the government protected the railway during the pandemic, with a package equal to "£600 for every household in this country", or "£160,000 per rail worker".
But he added that "this level of subsidy... simply cannot continue forever". The transport secretary also accused Labour of not caring about workers who will be trying to get to their offices next week amid the planned strikes.
"It is inexplicable how the party who style themselves as the workers' party don't seem to care about the fact that these people, that anyone that is trying to get anywhere will lose pay," he said.
Mr Shapps faced heckling from the Labour benches throughout his speech, with shadow work and pensions secretary Jonathan Ashworth branding the planned industrial action "Tory strikes". No passenger services will serve locations such as Penzance in Cornwall, Bournemouth in Dorset, Swansea in South Wales, Holyhead in North Wales, Chester in Cheshire and Blackpool, Lancashire.
There will also be no passenger trains running north from Glasgow or Edinburgh, and the last trains to and from London will be much earlier than normal.