“Kilnasaggart Bridge” was a whispered curse on the lips of train travellers in the days of Northern Ireland’s Troubles.
It nudges up close to the border that separates the six counties of Ulster in the United Kingdom from the Republic of Ireland.
The bridge was such a popular target for IRA bombers that uninterrupted travel from north to south was often impossible.
A groan would go up as the tinny tannoy announced that, because of problems on the line, all passengers would disembark at the Newry halt, travel by bus across the border and then clamber back on the train at Dundalk in the Republic of Ireland.
We trundled on, we trundled off. It added at least an hour and more like two to the journey. So much for the “express”. But at least we knew we had crossed the border.
Now, commuters sip posh coffee and sail past this once troubled spot, blissfully unaware of where the north ends, and where the Republic of Ireland begins.
The border is there, but it is not there and the bombs are history.
Drive along the modern motorway that links Belfast to Dublin and the only clue that you have crossed is the subtle switch from signposts in miles to those in kilometres.
Keen-eyed, you might spot the change in the markings on the sides of the road.
It is a child’s guessing game - north or south, are we there, aren’t we here?
About 50 years ago, it was easier. The good roads were in Northern Ireland - you knew you had hit the Republic when the potholes rattled the car.
The road signs in the south were more dramatic than the north. They came in sets and block capitals: SLOW; SLOWER; SLOWER STILL.
This border is 310 miles (499km) long and meanders from Carlingford Lough in the east to Lough Foyle in the west.
It was never a neat line. It is a squiggle across the map of Ireland – like an awkward child taking their crayon for a walk.
That line divides rivers, slices fields, cuts bridges in two and even, occasionally, divides the odd house.
There are homes where you can have your breakfast in the north and go to sleep in the south.
There are places where mobile phone reception in just one house fluctuates between north and south.
The days of the Troubles are behind us - days lived in the dark shadow of watchtowers and turrets are vanished.
But now the UK is getting ready to leave the EU, and the people of the borderlands are uneasy.
Up to 35,000 people commute across the border every day.
Hospital patients and schoolchildren and cross-border workers are among those who have to make the daily journey.
None of them wants a hard border, but the EU has stressed that there will have to be some form of customs control. What is a “soft” border?
Will thousands of people find themselves cursing daily in long queues at border points?
The village of Muff lies close to the border between Donegal and County Londonderry.
During the Troubles, cars queued at the Army checkpoint, where twitchy young soldiers with rifles rattled out the usual questions. Where are you coming from? Where are you going to? Get out and open your boot, sir.
Then it was on down a twist in the road and the Irish customs men were on their marks waiting to catch the locals with the contraband.
Now, you’d hardly know you were crossing.
A black corrugated hut at the old customs post is boarded up - weeds sprout from the chimney.
Over the bridge and you’re into the one-street village. It is tiny but boasts four petrol stations.
There is what used to be an old Irish ballroom - a big, squat building called Borderland. When Derry city burned in riots and bombings, Borderland was the escape – the dance hall down the road, where you jived your way into another world.
Marie Lindsay was born in Muff, but the city of Derry is centre stage in her heart. She lives in the hills just outside the village and has a foot in both camps.
Each morning she gets into her car in Donegal, in the Republic, and drives up through a little wood. Then it’s on through a housing estate and into Derry, where she’s principal of a girls' school, St Mary’s College.
She has lived her life along this border. Like thousands of others, she feels she has a double identity.
“I’m Donegal, born and bred. Donegal is in my DNA, but Derry is my home city, I feel I belong there,” she says.
Her journey to work is seamless these days – down what was once an “unapproved” road - spiked, so that people could not drive across.
As the Troubles in Northern Ireland escalated in the 1970s, the Army and police blocked and cratered the smaller roads to make all but the approved checkpoint routes impassable, and to stop paramilitaries crossing.
Lindsay has known a hard border - the interminable waits at checkpoints. They were dark days that no-one really wants to recall.
She has now grown used to peace and the ease of life.
On the evening drive home from work, she points out the spot where you have crossed.
“The road signs switch from miles to kilometres, the road markings change, but that’s it,” she says.
She carries two purses – a sterling purse for the north and a euro purse for the south. But both sides take each other’s currency at a decent rate. Many people carry two mobile phones – one north, one south.
Talk to any of the girls in St Mary’s, says Lindsay, and you’ll soon find they have roots in Donegal – a granny in Malin, an aunty from Carndonagh.
All down the years, city dwellers have taken a Sunday drive from Northern Ireland over the border to feast their eyes on the beauty of Five Fingers Strand, to nurse a pint in Buncrana, to treat the children to a ride on the swing boats by the shore.
But the links amount to much more than a Sunday stroll. There are good schools in the city of Derry and the health service is free.
Many people in Donegal send their children to school north of the border or are treated by the National Health Service - some officially, some unofficially.
There are pressing questions about students. Many from Northern Ireland travel to university in Dublin, Galway and Cork.
Others from the Republic of Ireland cross the border to go to Queen’s in Belfast and to Derry’s Magee College and the North West Regional College.
Lindsay is also concerned for the Donegal students who cross the border to go to the city’s further education college.
“They could end up having to make the 40-minute drive to Letterkenny whereas before it was just 10 to 15 minutes into college in Derry.”
On 23 June, 76p bought you one euro, but by the second week after the Brexit vote, that figure had shot up to 86p.
It would reach a high of 90p last October, before falling back slightly since.
For all those living in Donegal and working in Derry, the value of their sterling pay packets has plunged.
In recent years, Lindsay’s Donegal village has played host to young families from Northern Ireland, lured by affordable housing.
It has been a breath of fresh air – new life for the local primary school, tills ringing in the shops, a bustling community in the border village.
But Brexit is making border folk start to think twice.
Betty Holmes is a member of Donegal Action for Cancer Care. The group is based in the Republic of Ireland but campaigns to access nearby health facilities in Northern Ireland.
She is passionate about getting the best cancer care close at hand.
It’s a deeply personal campaign. Her father died of lung cancer a week after her seventh birthday - he had never smoked. Her mother died from breast cancer three years later.
When a new state-of-the-art radiotherapy centre opened recently in Altnagelvin Hospital, Derry, there was a sigh of relief from families on both sides of the border.
No more two-hour treks over the mountain pass from Derry to Belfast for those living with cancer in Northern Ireland’s western region.
No more five-hour treks from Donegal to Galway for cancer patients living in the Republic of Ireland.
“It is a good 308km to Galway and what sort of a journey is that when there is radiotherapy sitting a few miles across the border?” asks Holmes.
The journey to Altnagelvin Hospital is as little as 45 minutes from the top end of Donegal at Malin Head, she says.
The Irish government has invested in the new services in Northern Ireland.
Agreements in place between the UK and Irish governments mean there are currently places for 385 cancer patients coming across the border.
But Brexit weighs heavily on Betty Holmes’s mind.
“Our concern is what happens in three to five years when the real effect of Brexit is starting to be felt,” she says.
“Will the Irish government be in a position to pay what [is set] down as the cost of treating a cancer patient at Altnagelvin? Will that number be reduced from 385 to 200 initially and will it go down from there?”
The sharing of medical services across the border is not a one-way street.
“If you are the parent of one of the children from Northern Ireland who would travel to Dublin for paediatric cardiac care, then you might be asking what impact Brexit could have for those children?”
Ciaran Crilly woke up to the news of Brexit last June and immediately worried about his business.
Just up from Cloughoge church on the Newry border, where the Army posts once cast long shadows on the high hill, is the sweet factory – a family business set up in the 1970s.
Ten years before that Ciaran Crilly’s father, Peter, left for a sugary fact-finding mission, taking in the Mars factory in Slough, and then Blackpool to uncover the secret of getting the name through the stick of rock.
In the 1970s, as the Troubles raged in Northern Ireland, he came home, put his head down and set up a business. Now his son has the reins.
Before Spanish holidays were the norm, the Crillys made seaside rock, selling it from Portrush in Northern Ireland to Bundoran and Bray in the Republic.
This was the time when traditional sweets - bags of clove rock, bull’s eyes and brandy balls - still cast their spell.
On both sides of the border, they still love their sweets.
But Brexit was a blow.
“It was terrible. Our business has been going superbly this last 10 years, year-on-year growth, no issues. Then you have this shock and you ask why did it need to happen?”
The company was doing 75% of its business with the Republic of Ireland. When the UK exits Europe, if a trade deal isn’t reached, it could potentially face a 30% tariff in line with World Trade Organisation rules.
That would be a worst-case scenario, says Crilly, but possible.
For a while, Crilly considered upping sticks and moving a few miles down the road to set up in the Republic.
Instead, they decided to stay put and look at new markets. In January, Crilly’s Sweets had a stand at a trade show in Germany and picked up business in Australia and China.
They have been inundated with requests. Every emigrant craves the comforting taste of home.
“We gained a lot of business through expats in Australia. People miss the kola cubes, pear drops, clove rock, mixed balls and even the jelly babies and wine gums,” he says.
And, given the response from across the globe, perhaps Brexit could prove a blessing.
But it’s an anxious time.
“Half of our staff are from EU countries, such as Latvia and Poland. Will they stay?” Crilly doesn’t know.
Drive on for an hour along the border and it’s sheep day at Enniskillen mart.
The yard is a long line of muddy Land Rovers hauling trailers full of sheep and ewes.
Men in flat caps, jeans and wellington boots meander about.
Denzil Brady is 84 but wiry and keen-eyed. In all his years working on his father's farm in the hills around Enniskillen, he has had little time for the European Union.
“They're the greatest set of rogues in Brussels,” he says.
“They have farms nearly out of business with the whole pile of paperwork.
“With all those regulations, I fear for the young farmers in their 40s and how they'll suffer lives of misery.”
Hugh Maguire has a different view. He has farmed for more than 50 years up by the famous Marble Arch Caves. His land straddles the border and he's had his share of headaches.
He has cows and sheep, but some of them belong to the north and some belong to the Republic. It makes for two sets of paperwork and a few headaches.
Woe betide the Irish sheep that sets a hoof over the border and vice versa.
But Maguire believes the EU did a lot of good and Brexit is not welcome.
He remembers the old days of smuggling across the border. He remembers the hard border, the checkpoints and queues and he just asks himself what lies ahead now.
It could be a big step backwards, he says.
“Farmers cannot farm without the European single farm payment,” he says. This is the agricultural subsidy payment, based on the area of a farmer's land, to offset the cost of producing food.
James Johnston is the mart director - it's a family business that goes back to his grandfather's day.
He's a young man and he admits that, personally, he is no fan of Europe.
“The EC originally was very good in terms of promoting free trade and promoting peace and security within Europe.
“But I do think it has overstepped the mark as it has grown. Legislation-wise, it has just mushroomed. At its heart, it's quite an undemocratic system. So I can understand reasons for pulling out,” he says.
“However, where we are, here in this part of Ireland, in Fermanagh, we border with four of the southern counties, an open border is absolutely critical to peace and general well-being on both sides - free movement of people and goods.”
Johnston argues that it must be maintained, however Brexit pans out.
He'd like a more open border with the Republic of Ireland even than exists now.
“It's exceptionally difficult, virtually impossible to bring livestock across the border, sell them in this mart and for traders to buy them and bring them home again.
“It's easier for us to send cattle from the mart here to England and Scotland after a sale than to send them 10 or 12 miles down the road a stone's throw away across the southern border.”
The problem lies with animal health and biosecurity, he says. Different policies exist on each side of the border. And now there will be more change.
For farmers, the best-case scenario would be a post-Brexit free trade agreement, says Phelim O'Neill, a markets specialist for the Irish Farmers Journal. The worst-case scenario would see a very heavy tariff on agriculture products traded between the UK and the EU.
“In terms of where will hit hard for Northern Ireland, somewhere between a quarter and a third of milk produced in Northern Ireland dairy farms goes to Ireland for processing,” he says.
“So if you are one of those farmers, your milk will be hit with a very high tariff – it would not be viable to send it.
“It is the same for sheep. About 400,000 sheep each year go from NI to factories in Ireland for processing. If the WTO tariffs apply, then it simply would not be viable.”
People who own petrol stations along the border know all about boom and bust - trade depends on currency fluctuations and significantly lower fuel duty rates in the Republic of Ireland.
Enda McColgan, manager of the Texaco in Muff, says 90% of the garage’s customers come from Northern Ireland to top up.
Business is booming. There was one stage when demand was so great they even had to employ somebody to manage the traffic on the road outside.
Garage owner Colm McKenna remembers bombings, the checkpoints and the days of soldiers in ditches.
“If we had a hard border then we’d be going back 30 years in six weeks to six months,” he says.
It’s not hard to imagine who might target such a border, he points out. Some have warned that a hard border could be used as a justification for violence by dissident republicans who do not support the current peace agreements in Northern Ireland.
Not far away, at another crossing, Kevin Melarkey is the egg man on the border at Bridgend near Derry.
He's there at the farm shop seven days a week - in a small hut - selling eggs and bags of spuds. He has a good thick coat and a pair of mountain boots to keep out the cold.
When he gets a minute, he can stand outside his hut and rest his eyes on the blue hills of Donegal.
He's too young to remember much more than the queues at the checkpoints on a Sunday when half of the city decamped across the border to Buncrana or to buy cheap petrol.
Like everyone else, he does not know what Brexit will bring.
“We're in limbo, it's just a waiting game,” he sighs.
Brexit and border changes will be more significant for Northern Ireland, says Katie Daughen, head of Brexit Research and Support Services to the British/Irish Chamber of Commerce. Every year 31% of NI exports are to the Republic and 27% of its imports come from there.
The main sector to be affected is food and agriculture. “It’s worth over £4.5bn to the economy in the north and it’s by far the most exposed.”
Daughen lists a couple of examples of the all-island nature of the economy:
• Wheat grown in the south is processed in north
• 40% of chicken produced in the south is processed in the north
One of Ireland’s most famous exports faces similar problems.
Guinness is brewed in Dublin in the Republic of Ireland. But it’s sent north of the border to be bottled or canned before returning to Dublin for export to the world.
But it is not all doom and gloom. There are opportunities out there too.
The border’s disappearance was a gradual shift - like ice melting.
After the 1998 Good Friday Agreement, things moved slowly.
But the dragon’s teeth - ugly concrete blocks squatting on hundreds of country roads linking north and south - were suddenly yanked. The soldiers in their camouflage passed out of view.
In 2003, they took away the checkpoint at Newry. They pulled down the ugly iron cage, the military turret high on the hill above the church at Cloughoge.
The people who felt safer for the presence of the Army on the hilltop called it a watchtower.
Those who resented the Army, and their high power cameras, preferred “spy post”.
It was close to that Newry border where Lord Justice Gibson and his wife Cecily were killed by an IRA bomb in 1987.
A year later, Robin and Maureen Hanna and their son, David, six, died in an IRA explosion after crossing the border.
The family from Hillsborough in the north were returning from holiday when their vehicle was mistaken for one belonging to a senior judge.
The big military turret went up on the hill after that. It was a stretch of road that became a no-man’s land between north and south.
It was not a place for a friendly chat - there was tension in the air, the soldiers were edgy.
Crossings were never easy.
Many resented the waiting and the questioning. People were afraid they might get caught up, a sitting target for a bomber. Or scared that a soldier might even get trigger happy.
But there was another side to the old border too.
The game of “catch me if you can” with the customs officers still raises a smile.
Butter was cheaper on one side – hide it in the pram and sit the child on top. It was all the sweeter for being illicit.
Young couples from the north took the train to Dublin to buy the wedding ring. There are tales of dangling the ring out of the train window on a thread on the way home to evade the keen eye of the customs man.
In Fermanagh, drive down past the town of Enniskillen and on to the border towns of Belcoo and Blacklion and you see how past and present merge. The stone bridge marks the crossing point between north and south.
The bus stop in Belcoo has two sets of signs – a blue and white sign for the Ulsterbus and a green one with a greyhound for Bus Éireann.
The street signs are in both English and Irish.
Harold Johnston has an old-fashioned shop just over the bridge in Blacklion. His grandmother opened it in 1901.
“She was a trained seamstress and had five dressmakers upstairs at one time. She used to do wedding dresses and red flannel petticoats.”
A century later, her grandson presides over an Aladdin’s cave.
It is a drapery and a clothes shop and a wool shop and whatever you like. The shoe boxes are piled high, there are rolls of oilskin tablecloth propped up.
From the door, Johnston can look left to where the customs post and Irish gardaí once stood, checking the cars coming south.
“There were 43 guards and six sergeants at that border,” he says. “We had 24-hour cover and two shifts. We had patrol cars patrolling the back roads.
“They were stationed in the barracks on the left. The young lads were sent up from Dublin for training along the border.”
In the 1930s, the Depression hit hard but on 3 September 1939 trade exploded on his side of the bridge when war was declared.
“They were putting restrictions in the north and it was scarcity this and scarcity that. But we had lots of butter and sugar.”
Smuggling was rife.
Johnston tells a story about the undertaker in Blacklion in the Republic who was running short on shrouds, but had a friend across the border in Belcoo who knew another man that could get him some.
The problem was getting them over the bridge from north to south.
“Yer man came into the bar in Blacklion and said the parcel had arrived and he had it with him,” Johnston says.
“So he went into the kitchen and he had on a coat three times too big and he opened it and he had put all the shrouds on himself and walked over the border like that.
“As he took the shrouds off in the kitchen at the back, yer man looked at him and said: ‘It’s the first time I’ve ever seen a man taking a shroud off’.”
During the Troubles, there were just 20 official border crossings between Northern Ireland and the Republic. The British Army shut down, spiked or cratered the rest.
With peace, the country relaxed, breathed a sigh of relief, and unspiked the roads.
Trade and business became more fluid – it blossomed. Businesses in Northern Ireland set up offices in the Republic and vice versa.
Seamus Leheny from the Northern Ireland Freight Transport Association knows the pain of those whose businesses may be disrupted by Brexit.
An Irish revenue commissioner has said up to 8% of freight crossing the border might be subject to checks after Brexit.
With a minimum of 6,000 lorries trundling over the border every day, you begin to see the scale of the problem.
“That makes at least 500 lorries that could be checked every day," says Leheny. "Added to that is the thought that drivers selected for checking might have to drive away from the main flow of traffic to a specific post – and distance costs money.
Even if there are to be checks it doesn't necessarily follow that there will be a string of traditional border posts with long queues of lorries.
On the ground, people are thinking ahead.
There are cross-border meetings and countless committees working out the logistics of a border that is longer than the length of the island of Ireland.
At government level, civil servants in London are getting their heads around the conundrum of Northern Ireland.
One thing that looks likely to continue is the Common Travel Area (CTA), the bilateral UK-Ireland agreement that allows for free movement of UK and Irish citizens between Ireland, Northern Ireland and the rest of the UK.
The arrangement allows Irish and UK citizens the right to work, to access public services and to vote in certain elections, and Brexit Secretary David Davis has described the continuation of the CTA as "non-negotiable".
Jane Morrice, former head of the European Commission office in Northern Ireland, helped broker the Good Friday Agreement during her time as a politician. She wants to maintain the status quo on the island of Ireland.
She is proposing that Northern Ireland should have honorary membership of the EU after the UK's departure.
“We've made such good progress since the Good Friday Agreement. Removing the border and removing borders in mind as well as geographically has been hugely successful and we cannot allow ourselves to halt that or reverse it in any way,” she says.
“The role played by the EU in the peace process was instrumental.”
Border dwellers are hardy as the weeds and thistles sprouting from the old huts at the customs posts.
They have come through partition and war and the Troubles.
Harold Johnston tells the story of a villager in the 1920s who travelled up the road to Enniskillen in Northern Ireland for his groceries every week.
Partition hit home on the very day of his weekly shop.
On his return journey, a fresh new customs hut had sprung up at the border and a man in a starched uniform was waiting for him.
“You can’t bring those goods into the Free State,” said the customs man.
“But I always have,” said the man.
“Well, you can’t now,” said the new officer.
The man turned back for a sit and a think in nearby Belcoo, Northern Ireland.
What did he do?
Johnston pauses and smiles. “He sat and waited for the customs officer to shut up shop for the night and sure didn’t he just walk over the border.”
There is always a way.