Easter mini-Interrail return, day four: Toulouse - Périgueux

I’ve been looking for an excuse, however fragile, to contrive a journey involving a resurrected Intercités de Nuit to see whether it's a good way of making a future France-UK dash less stressful and more, well, decadent.

A normal person would say there’s something undeniably romantic about the idea of a night train; the gentle lulling through the countryside as you snooze, lights that swoosh past the window, not knowing whether you're actually moving or just hallucinating. But really it's a tiny inescapable hostel on wheels where the real concern is the possibility that the person in the couchette above you has just had a curry you'll get to experience later, or that someone will start snoring just as you're ready to drop off – those kinds of things. The reality is that if you can't sleep, it's an excruciating time.

I did not have a good night's sleep.

There was nothing wrong with the night train, the bed – it was perhaps a tad short for my height – my magical sleeping bag, nor anything else. Nothing. It was all wonderful. I simply couldn't sleep, and it wasn't for lack of trying. Perhaps it was because I'd spent most of yesterday mainlining free coffee and had finished the day stuffed with chips and espresso, but whatever the cause I spent most of the night either looking at my phone to see where we were, or trying desperately to exorcise whichever earworm had taken up residence. I made various efforts at contorting myself into a snoozy-time sleepy position that didn't make it look as if I was bunny-boilering the person on the bed opposite. That was fun.

They should have little curtains on the couchettes in first class, I thought. There were no sheep to count. I made sentences using the alphabet backwards.

I couldn't even get up and walk around, because that would have meant opening the door to the compartment and disturbing my fellow travellers – all somehow sleeping like babies. Nor could I even deploy the train slippers because they were in my bag which I'd helpfully put up on the baggage rack as it wouldn't fit under my bed. Even that contributed in its own way to my insomnia as I was terrified that a sudden sharp left turn would send it hurtling down the metal ladder onto either myself or the girl in the bed opposite.

My fears were ill-founded, and I think I might have managed some sleep between Angoulême and Bordeaux, where it felt like we were stopped for a while. As I was not asleep for all of it, I also know that the train went from Austerlitz for a second stop in Les Aubrais, then chugged slowly onwards past Poitiers and Angoulême to Bordeaux, before turning left and slowly making our way to Toulouse-Matabiau via Montauban. I was, I suppose, at least awake to experience the whole journey – every sleepless moment of it – and to consider that I should book an upper bunk next time because there's room for luggage where your feet go, which means the bed is slightly longer. Did I mention curtains?

Anyway. This is unimportant. After a lovely day's grazing to Paris on the train, I experienced nine long, tedious, hours holed-up in a little room in a rolling metal box with three other people who were flat out and happily dreaming. They weren't even snorers, farters, or phone-users – they were the perfect compartment companions. At least if you're travelling with someone who snores you can wake them up and ask them to stop. Or if you're with someone who doesn't, you can wake them up to ask if they're awake. I went to the toilet at about 4am where I met a man wearing train pyjamas – to go with the slippers, of course! – at the end of the carriage. I was, at least, on a train, but it was not the sleeper from Bodø to Trondheim. There wasn't even anything to look at outside, because it was night.

I looked at my bag again and wondered whether it was likely to fall over. It didn't. As my Interrail pass ran out at midnight, I booked a ticket train ticket to Agen, hoping that the experience of using SNCF Connect might be enough to extinguish any desire to remain conscious. My bag stayed resolutely put, no matter how long I watched. At Montauban, the girl in the bunk opposite burst into a last-minute frenzy of activity to get her and her suitcase out of the compartment, then came back a few minutes later when she realised we hadn't yet reached Toulouse. That was not enough to wake the lad up in the bunk above her.

We were on time. Some people were brushing their teeth in the corridor. After I'd pillaged the compartment for the unused sleepy-kits, I headed straight for the Salon Intercités de Nuit where a very chirpy lady was handing out fluffy towels and cups of coffee to rouse back to life those of us who had just arrived after a night's sleep – or lack thereof. This was an unexpected but welcome part of the journey which led me to abandon my plans for breakfast and stay in the comfy bubble of the lounge until it closed at half-past nine.

The shiny red TER liO train left for Agen twenty minutes later. I made this journey last year on the way back from Toulouse, and today was less eventful than last time but prettier because the sun was out. There may have been some snoozing.

In Agen, there was plenty of time for a bit of mini-tourism, and my first destination was the cathedral, a Unesco World Heritage Site built in the 12th century which offered welcome respite from the clear sky and beating sun. It's quite unassuming from the outside – you'd be forgiven for thinking that the cathedral must be somewhere else because it's not exactly imposing – but the interior is wonderful.

The church was used to store grain during the French Revolution before being reopened in 1796 and becoming a cathedral in 1801 as the former cathedral was destroyed during the fighting. The interior decoration was entrusted to a painter from Toulouse in 1829 who took forty years to complete the work, presumably having needed a good few years to submit a quote and then a few more to actually turn up and start it. It's probably just as well he took his time as the result is a splendidly warm-feeling from the blues and ochres used to depict the martyrs of Agen among more traditional Christian themes.

Save for one man doing Pilates on a pew, the place was empty and a proper disconnect from the outside bustle of lunchtime Agen. Cathedral ticked off, I set off to find the one piece of street art in Agen on Street Art Cities and once I'd crossed that off my list, I felt there was little more to do than find something for lunch as I had no intention of walking around with a backpack, no matter how tactical, more than was necessary in the heat.

I could probably have saved myself a fortune by eating in a little bistro on a square somewhere, but I decided to go back to the station just because I enjoyed it so much last time. I had the risotto de coquillettes à la truffe followed by a café gourmand, which was verging on the obscene, which in total came to 32€ including the beer – because sunshine. It was expensive but rather good, and I took it on the terrace under a parasol to enable people-watching.

I had to fight to stay awake on the 14:24 train to Périgueux which, for once, was timetabled to coincide with an onward bus meaning I didn't have to go via Bordeaux. This made me extremely happy for I have never been on the route between Agen and Périgueux before and it is utterly delightful.

There are nine stops along the 137 kilometre-long single-track route, which takes a very pleasurable two and a half hours to complete. As we left Agen, I thought it delightful that young children would run en masse to the bottom of their gardens to give us jaunty waves as we passed, harking back to the wonder days of steam. In this day and age in the suburbs of the prefecture of the Lot-et-Garonne, it seems only one finger is required for the greeting proffered, although both hands are used. The driver didn't toot.

The weather was particularly fine and with the sun mostly above us, the light was very kind to the landscape along the way and made it even more glorious. I was confused to see that Le Buisson-de-Cadouin, a commune of approximately 1,400 people, has a railway station with six platforms. There must be something going on.

Along the way there are rivers, valleys, trees – lots of trees – villages, and just general postcard-worthy vignettes all along the route and I could do it in the opposite direction on the other side of the train just to be able to take it all in. As we moved north the children were slightly more sophisticated than the ruffians of Agen, and they gave proper jovial greetings which elicited friendly reciprocal friendly toots from our driver.

The line between Limoges and Agen was originally part of an ambitious project from 1853 to build a railway between Paris and Madrid, which would pass through Limoges, Périgueux, and Agen, and then – after a few more stops onwards through Tarbes and Zaragoza – terminate in Madrid. It didn't happen, and fizzled out before reaching either border or capital. Having no terminal in Paris, not serving any major cities, and not reaching any sea or borders, the Compagnie du chemin de fer Grand-Central de France was doomed from the start and ran out of money in 1857.

After inheriting the concession agreement from Grand-Central, the Limoges to Agen line was finally constructed and eventually opened in 1863 under ownership of the Compagnie du chemin de fer de Paris à Orléans. It runs over rivers and along the Dordogne valley, passes through five tunnels and over seventeen bridges, some of which are stone viaducts that have little aesthetic quality when you're in a train passing over them besides the views from above they afford either side.

I slept for a good portion of the first hour, occasionally awoken by truffles repeating on me, but eventually mustered the energy to stay awake for some spectacular scenery the further we got towards Périgueux where we arrived at 16:54.

In Périgueux there was time for a swift half over the road from the station before my bus whisked me home to bed. No bunks, no earworms, no slippers required.