Disruption is worsening as more drivers than expected refuse to cross picket lines.
Merseyrail had hoped to run almost half its services, but "many" drivers took the decision not to work today.
The company said it was running around 20% of services, far fewer than previously advertised.
Trains were still running on most routes, every half an hour, but they were not stopping at every station.
Merseyrail bosses have told passengers using their strike-hit services this morning to expect overcrowding.
The operator is one of two in the North West where staff have walked out in a dispute over the roles and responsibilities of guards on their networks. Tens of thousands of journeys will be disrupted as staff at Northern Rail also walk out.
Merseyrail's Andy Heath says their customers should check online for updates before setting off:
Manchester Victoria train station appeared empty at 7am this morning, as members of the RMT union walk out on strike.
Tens of thousands of journeys will be affected today as union members stage a 24 hour strike on Merseyrail and Northern Rail services.
The strikes are likely to see more than half of all services cancelled in the North West.
The rail union, the RMT, says proposed changes by rail operators could affect passenger safety. Tens of thousands of journeys will be affected today as union members stage a 24 hour strike on Merseyrail and Northern Rail services. The strikes are likely to see more than half of all services cancelled in the North West. Daren Ireland form the RMT says he believes passengers support their action:
Bosses at strike hit, Northern Rail, have asked their customers to check their website before setting off, today. The rail operator has been hit by a one strike by the RMT Union in a row over future responsibilities of guards on their network. The Union claims the changes could affect passenger safety. Sharon Keith from Northern Rail says some services will still be running:
All travellers in the region are being urged to plan their journeys and check before they travel because of industrial action on both the Merseyrail network and Northern services today.
While train users will be most directly impacted, the whole transport network is expected to be busier as people find other ways to travel.
Merseyrail bosses say services are planned to run every half hour on all routes from around 7am to 7pm. All trains will be six carriages long. However, passengers are strongly advised to check the Merseyrail website and Twitter feed before travelling as it is possible that timetables will change prior to, as well as during, strike action.
Meanwhile, passengers who travel with Northern are also advised to check before they travel as the operator will also be running a greatly reduced, and revised, timetable. Services by other mainline train operators will continue to run as normal.
Key advice for everyone needing to travel:
· Check before you travel: If you're a rail user plan based on current information available, but be prepared to adapt your plans as timetables may change on Monday 13th.
· Rail stations are likely to be busier as a result of reduced rail services. Don't aim for the last scheduled train, get there early.
· If you're not a rail user, you're still likely to be affected as people find alternative ways to travel. Leave longer for your journey and avoid travelling at peak times where possible.
· Bus may be a good alternative for you on strike day, with an extensive network across the region. Services will be monitored and strengthened on key routes.
· Ferries will be a good alternative if you're travelling across the River Mersey, with frequent commuter services and free car-parking at Seacombe for 370 cars. Valid cross-river rail tickets and passes will be accepted, including for cyclists. Current arrangements remain for the cross-river bike bus.
· Stick to public transport wherever possible to reduce congestion on key routes such as the Mersey Tunnels and roads in and out of the City Centre.
· Speak to your employer about whether there is any flexibility in working times or the possibility of working from home.
· If you have no option but to drive, consider car sharing.
· For the latest on Merseyrail services visit www.merseyrail.org/strike
We expect to be able to run the revised timetable published earlier this week, as long as other staff who are not on strike come to work as normal.
However, it is possible that services change prior to, as well as during, strike action, so we strongly advise passengers to check our website and Twitter feed before travelling.'
"We are acutely aware of the important role that Northern plays in keeping the north of England moving, would ask for your patience on Monday, and ask all our customers to individually take time to consider whether your journey is necessary and if it is, please plan carefully."
Up to 2,000 workers at three rail companies are on strike, threatening some of the worst disruption since the industry was privatised.Read the full story ›
Tens of thousands of people across the North West face travel disruption on Monday as members of the RMT union walk out on strike.Read the full story ›
Northern Rail services remain shut today as engineering works are carried out across the region.
Yesterday Network Rail defended the line closures after it was revealed £103 million worth of improvements were happening across the country.
The Shadow Transport Secretary has spoken about the closures:
"Tory ministers' handling of the Boxing Day rail standstill is making it much harder for families and friends to visit one another this Christmas break.
In opposition the Tories attacked the Boxing Day rail shutdown. They've now had more than six years to do something about it but haven't.
Their lack of action, even despite the chaos of previous years, gives the impression they don't really care about it at all. The Tory hypocrisy on this issue is astounding."
Network Rail has defended Christmas rail closures, by justifying that this is the best time of year for engineering work to be completed.Read the full story ›