‘Well, I’m off to Burtonport tonight,’ I say.

‘Where they brew Burton beers? Sounds very exotic,’ snorts Archie.

‘No. Burtonport, a fishing village on the far Atlantic coast of Donegal, the last stop on the Londonderry and Lough Swilly Railway.’

Between us, we know countries as far flung as India, Ceylon and China, yet agree that surely nowhere could possibly be more exotic than Burtonport, and that I am to report back its wonders over Guinness and Jameson.

I walk up to Euston only just in time to board the Stranraer sleeper. By chance – or good luck – I have a third-class berth to myself, in a comfortable former London and North Western Railway 12-wheeled sleeping car. Even though we set off just before 8 p.m., I am fast asleep soon after the gently swaying train has passed Watford, and only wake up when we pull into Carlisle in the early hours of the morning. Keen to find out which locomotive has taken me this far, I slip my coat over my pyjamas and my bare feet into brogues, and walk between pools of lamplight and wafts of steam from the train’s heating pipes towards the bulldog silhouette of 6122 Royal Ulster Riflemen. Built five years ago at the North British Locomotive Works in Glasgow, this is one of the London Midland and Scottish Railway’s (LMS) powerful Royal Scot 4-6-0s. Her large boiler, crowned with the squattest of chimneys, gives her a truly massive, hunched-up appearance.

If he had been able to get his own way, Henry Fowler, chief mechanical engineer of the LMS would have built a longer – if only slightly leaner – class of four-cylinder compound Pacifics, based on the latest French practice, instead of the three-cylinder Royal Scots. Fowler’s Pacific, which never got beyond the drawing board, was seen by management as being too expensive a proposition, and probably a little too exotic for the conservative tastes of Derby works. The Royal Scots were built instead, and in a rush, by North British – in association with Herbert Chambers, the chief draughtsman at Derby. They might not be Pacifics – nor, I gather, as efficient as the latest French compounds – but the Royal Scots are potent and reliable machines.

As Royal Ulster Rifleman steams away to be serviced at Upperby shed, I watch a pair of smaller locomotives, coupled together, backing towards the sleeper. The train engine is 40936, a brand-new LMS 4P class compound 4-4-0 – resplendent, like Royal Ulster Rifleman, in gold-lined crimson lake paintwork. The compound’s pilot, in the same livery, is an engine new and exotic to me: 14672, a lithe and handsome 4-6-0. Her works plate tells me she was built in 1911 by North British, for the Glasgow and South Western Railway. I have to ask her driver, amused to see me on the platform at this unsocial hour, what this elegant engine is. One of Mr James Manson’s express locos, this is her last month in service. The engine is in fine shape, but the LMS is standardizing its fleet.

Unable to get back to sleep, I open the ventilator above my window to listen to the locomotives as they pound northwest from Carlisle, over the border and on through Dumfries, Castle Douglas and Newton Stewart, on the undulating line to Stranraer, 73 miles away, where we pull in at 6 a.m. The ferry across the Irish Sea to Larne is berthed right alongside us. On the platform I observe my fellow passengers. They include a sizeable contingent of what must surely be businessmen, politicians and civil servants, some hanging on to their hats and dignity as the wind scudding across Loch Ryan blows away morning cobwebs and English trilbies and bowlers. This is the shortest of the Irish Sea crossings – just 45 miles and two and a half hours – and much the favourite for those lacking sea legs.

Our ship is the handsome new Princess Margaret named after the younger daughter of the Duke and Duchess of York. I have details of her – the ferry, that is – in my bag. Here they are. Built by William Denny of Dumbarton for the LMS and launched last year, she weighs 2,523 tons and can carry 1,250 first- and third-class passengers, 236 cattle, 37 horses and a sizeable amount of cargo. I think the cattle must come from Ireland as I don’t see any boarding here at Stranraer. No horses either. Princess Margaret, I read, is powered by a pair of Parsons steam turbines producing a combined 7,462 shaft horsepower at 269 rpm. Her top speed is 21½ knots.

I make my way to the cafeteria for breakfast, as members of parliament and officer ranks of the Civil Service remain tucked discreetly behind the doors of their first-class cabins. We slip anchor at 7 o’clock – sunrise – steaming smoothly from the loch. On deck, I listen to the stern hiss of water along the sides of the ship as she cuts into the Irish Sea. At her stern, I watch water churned into furious channels of foam and spray.

I find myself inwardly singing along with Bing Crosby’s ‘Where the Blue of the Night (Meets the Gold of the Day)’, which somehow segues into Duke Ellington’s ‘It Don’t Mean a Thing (If It Ain’t Got That Swing)’. The sea certainly swings, turning decidedly choppy. I retreat to the dining room. A well-dressed, unfazed English family at the next table tucks into an ambitious breakfast. The son is engrossed, between mouthfuls of scrambled egg and bacon, by the latest copy of The Magnet, and its slightly incongruous stories of Billy Bunter on the one spread and exotic travels through the empire on the next. I can’t help noticing that the cover features an illustration of the Great Western Railway’s Cheltenham Flyer, the world’s fastest scheduled train.

His sister is reading The Girl’s Own Paper, and their mother, dressed in well-cut tweeds, lights a cigarette. On the table, she has a copy of Cold Comfort Farm by Stella Gibbons, a novel published last month that’s said to be very funny. If I hadn’t fallen asleep, my own reading for the Stranraer boat train was to have been Freeman Wills Crofts’ Sir John McGill’s Last Journey, the story of a Northern Irish industrialist murdered, apparently, on the Stranraer sleeper. A part of the attraction, for me, is that Crofts is a retired civil engineer with the NCC (Northern Counties Committee, the Northern Irish division of the LMS) turned detective fiction writer.

I very much enjoy bobbing about on water, but Stranraer and our Charlie Chaplin’s Gold Rush–style meal, our plates sliding from one side of the table to the other, are soon memories as we head into harbour at the head of Lough Larne. Out on deck, I can see gulls screaming, terns wheeling and cormorants skimming across the waters. I glimpse emerald fields over the rooftops of terraced dockside houses, as well as railway yards, cranes, warehouses and squat, glum-looking churches.

And there, on the other side of the NCC tracks for Belfast, is, to my English eyes, a wonderfully exotic sight. A purposeful 2-4-2T narrow-gauge tank engine, crimson lake liveried, is waiting at the head of a train of three corridor-connected coaches that look like the latest LMS main-line designs shrunk to fit the NCC’s narrow-gauge lines. I beetle down to this train from Princess Margaret as quickly as I can, as do those few businessmen and civil servants not heading for Belfast, and the English family.

What a fine and unexpected train this turns out to be. Aside from its compelling engine, 104 – a two-cylinder compound designed by Bowman Malcolm, locomotive superintendent of the Belfast and Northern Counties Railway and built at York Road, Belfast in 1920 – it is very smart indeed. The four-year-old carriages boast steam heating, plush upholstery, and lavatories, too.

This is the Ballymena and Larne boat train. With three stops along the 3-foot gauge line, we’re scheduled to run the 25 miles to the junction for Londonderry at Ballymena in 64 minutes. While the Cheltenham Flyer takes only a minute longer to run the 77 miles from Swindon to Paddington, the narrow-gauge Irish train is not slow considering the terrain. After easing our way around the harbour and then away from the stop at Larne Town, 104 gets quickly into her efficient compound stride. The first 12 miles of the trip prove to be an arduous climb through beautiful green farmland fringed with purple hills with gradients as steep as 1-in-36. We crest the ascent at Ballynashee, 600 feet above sea level.

Accelerating rapidly, we are now running at over 30 mph as we head south-west to Kells – and, from there, north at a clip to Ballymena, where we join the main line from Belfast to Londonderry. At Ballymena, our driver tells me that we’re lucky to have 104 on the run today. The boat train is very often in the hands of one of the ungainly Atlantic tanks built by Kitson & Co. of Leeds in 1908. Nominally more powerful than the compounds, these are prone to slipping – making something of a misery of the long climb up from Larne in wet weather, which is commonplace here, of course. One of these 4-4-2 tanks is at work shunting a string of goods wagons while we chat. The rest of the compounds run the Ballycastle to Ballymoney line further north. ‘But,’ says the driver, ‘we’d sure like them back on the Ballymena.’

I can’t help noticing that the English children waiting on the Londonderry main-line platform are eating Mars Bars, a new tuppenny chocolate bar made in a factory in Slough passed every day, at speed, by the Cheltenham Flyer. But here comes our Derry flyer heading into Ballymena station, a smart seven-coach corridor train led by a brightly polished NCC 4-4-0. This is U2 class No. 74 Dunluce Castle, one of the ‘Scotch engines’ built in 1924 by North British of Glasgow. She is clearly modelled on a Midland or LMS 2P 4-4-0, although William Kelly Wallace, locomotive engineer and civil engineer of the NCC from 1922, supervised the design. Only recently, Mr Wallace introduced colour light signalling – the first in Ireland – at Belfast York Road, the terminus from which Dunluce Castle departed earlier this morning.

The other thing I can’t help noticing is the width of the NCC track. Irish main lines adopted the 5-foot, 3-inch gauge, rather than the standard 4-foot, 8½-inch mainland gauge. I find this particularly interesting because I attended a lecture in Oxford earlier this year given by a Harvard archaeologist who has been researching the paved and grooved trackway the ancient Greeks engineered across the Isthmus of Corinth in around 600 BC. This trackway enabled ships, and perhaps even fighting triremes, to be pulled for five miles overland between the Ionian and Aegean seas, saving a great deal of time. This early form of railway was in use for 650 years, and Aristophanes refers to it in his comedy Lysistrata. The distance between the grooved tracks was exactly 5 feet, 3 inches. Irish railways have a classical pedigree.

The Londonderry train gets into a 60 mph stride before stopping at Ballymoney, where I lean out of the window to watch a pair of 3-foot-gauge S class compound 2-4-2Ts at work. Our next stop is Coleraine, where passengers can change for Portrush and the Giant’s Causeway Tramway. I would do so if I had another week in hand, but exotic Burtonport calls, and it’s still a long way off. It’s midday now as we cross the River Bann, and, as if by sleight of hand, the scenery changes from the engagingly bucolic to the stirringly romantic. It’s as if the poet Coleridge were in charge of the landscaping. Skirting the left bank of the Bann, we steam towards Castlerock and between the two tunnels – the longest in Ireland – passing below and through the former estate of the eighteenth-century Lord Bishop of Derry, the Suffolk-born Frederick Hervey, Earl of Bristol.

Between the tunnels, I stretch my neck up to see the Mussenden Temple, an exquisite classical rotunda overlooking the North Atlantic. I know from my interest in architecture that its design is based on Bramante’s Tempietto in Rome, itself based on the Temple of Vesta at Tivoli, which I cycled to along the Via Appia only last year. The architect of Bristol’s Irish tempietto was most probably Michael Shanahan, who accompanied the eccentric and philanthropic earl on at least one of his many visits to Italy.

The tempietto is, in fact, a library, commissioned in 1783 as a wedding present to Bristol’s favourite cousin, Frideswide Bruce, who married Daniel Mussenden, an elderly London banker. Said to be Bristol’s lover, she died in 1785. The inscription around the building, which I know – but cannot possibly see, of course, from the train at 30 mph – reads:

We canter down to the white sand beaches of Benone Strand, our track right by the rolling, white-horse ocean – I see either dolphins or porpoises revelling in the swell of the sea – and with the long looming crags of Binevenagh Mountain shadowing our progress inland.

Cutting off Mulligan Point, we lope past Bellarena station and find ourselves alongside water again, crossing a bridge over the River Roe and skirting Lough Foyle. On through farmland, we rumble over a further bridge across the River Faughan, and – following the curves of the banks of the River Foyle into Londonderry – come to a stand under the glazed roof of the NCC’s Waterside station, a sandstone bui...