There are delays of up to 40 minutes on First Great Western and CrossCountry services at Totnes due to a signalling problem.
The lines have now re-opened but trains may be subject to knock-on delays.
The disruption is likely to continue until around 9 am.
Protesters are taking their battle against a one-way traffic scheme to the High Court. Hundreds of people in have been campaigning against the decision to reverse the traffic flow in Totnes.
The case will be heard on 12 February.
Train services between Plymouth and Totnes are being disrupted while engineers are checking out a problem on the line.
First Great Western are organising replacement buses, but at the moment passengers are having to make their own way between the two stations.
Trains from Totnes to Plymouth are not affected.
It's hoped that the situation will be resolved by midday.
A new app will allow people to pay for goods and services in Totnes pounds using their smart phones.
The town has had its own currency for several years, encouraging people to trade locally.
The phone app has been developed by the team running the more recent Bristol pound, which has been taken up by 500 traders.
Hundreds of protestors marched today, calling on Devon County Council to re-open the High Street to traffic through the centre of Totnes.
Walking up the High Street where they can no longer drive, opponents to the road rearrangements in Totnes say it's an economic disaster for the town.
Actor Peter Richardson says: "All the people who say I like Totnes with no cars and stuff are just signing up to a town that is going to be empty in the winter and shops will die because they can't sustain and they can't make it work."
Around two to three hundred locals marched up the street before holding a rally demanding a return to how it was. One of the campaigners said: "Devon County Council are destroying my town. We want shared space, Devon County Council please listen."
But the local authority says far from harming business, trade has improved, along with safety for shoppers. And those who prefer the new system weren't afraid to confront today's protestors.
Alan Fuller is pleased that commuters can't race up the High Street.
"The people who drive through in the morning, the rat runners from Torbay through to Plymouth direction, make this an unbearable street. Since the road has been reorganised I think it's a much more pleasant place to shop."
Around three hundred people staged a protest march in Totnes today to try to change the road layout in the town.
The campaigners say traffic should be allowed to return to the High Street as shops are closing as a result.
But those in favour of the new system say it's created a much more pleasant environment in the town centre, that is safer for shoppers.
Cornish-born actor, John Nettles - famous for his roles in Bergerac and ITV's Midsomer Murders has taken on a new role - that of honorary patron of the Mare and Foal Sanctuary in Littlehempston near Totnes.
ITV News West Country presenter Kylie Pentelow caught up with the star, who recently moved to Devon, at the Sanctuary earlier today.
A Devon MP has called for schools to do more to tackle the childhood obesity epidemic. Dr Sarah Wollaston wants youngsters weighed every year to ensure schools can pick up on any unexpected increase in their size.
One in five children are currently classed as overweight when they start primary school in Devon and Cornwall - and one in three when they leave. Francesca Carpenter reports:
Totnes MP Sarah Wollaston has called for children to be weighed at school to help prevent obesity.
Dr Sarah Wollaston said it was wrong primary pupils were only weighed in reception class and year six.
Instead, they should be put on the scales every academic year so their weight and health can be monitored.
She also called on food companies to charge more for fizzy drinks, as they were laden with sugar and could push children into obesity.
Without urgent action the health service will struggle to cope with the raft of long-term conditions coming down the track, she said.
Low-income children were more at risk of obesity than their peers, dubbing it "a very important cause of health inequality, according to a GP turned MP.
The chair of the Health Select Committee, Sarah Wollaston told Good Morning Britain 12% of children from the most deprived backgrounds were obese when they started primary school, where as "24% being obese," by the time they finished primary school.