The advance information was clear – very clear.

“There are no toilet facilities on board … PLEASE CONSIDER CAREFULLY THE AMOUNT OF LIQUID YOU CONSUME.”

(Note: the capital letters are as per the original).

Anyone who has travelled on a Southern coastway train since 2010 will be all too familiar with the lack of toilets and catering on board the Class 313 trains. And those with children will have many times issued the “it’s just a few more stops” plea for juvenile bladder control before a chance to use station toilets … or had to break their journey before their destination and wait for a later train.

They are the oldest rolling stock on the national network. They have scuffed carpets and worn seats. They have no tables and no charging sockets. They have no air conditioning and no open corridors.

But the good news is they are about to disappear from Southern’s fleet. All 313s will be gone from Southern routes when the timetable changes on Sunday 21 May.

‘Not before time,’ many people will say. Rail campaigners and passenger groups have long called for the trains to be replaced with more modern rolling stock.

I joined rail enthusiasts and Southern staff on the ‘Sussex Rambler’ farewell tour organised by the Branch Line Society and Southern on Saturday 29 April to mark the end of the Class 313s’ 40+ years in service.

The blurb from the organisers also made clear “there are no catering facilities on board this charter”. After many years of journeys on these trains in Sussex, I knew this already. I came prepared: packed lunch and flask of coffee to hand.

It was a day of contrasts. It started with my journey to Brighton ahead of the approximately 249-mile charter trip across the Southern coastway region.

I had a wry smille on my face as the first leg of my day out was on a shiny, new Gatwick Express train complete with comfortable seats, toilets, tables, sockets and crystal clear public address announcements.

I arrived at Brighton 40 minutes before the scheduled departure and small groups of enthusiasts had already gathered on Platform 3. I got there just in time to see the special Class 313 units pull into the platform. A makeshift headboard displayed the charter service name with a farewell message.

The two units were 313201 (with the blue and silver livery) and 313213 (with the green and yellow livery).

My fellow passengers were of a type. Predominantly white, male and elderly – the trainspotters of yesteryear. I was surprised to see many of them still carried notebooks with lists of engine numbers which they dutifully crossed off en route.

People gathered round the doors waiting for them to open for a chance to board this special train. Passers-by noticed the attention being given to this one service among all the others at Brighton station and stopped to ask what the fuss was all about.

Some seemed interested and took pictures; others just wandered off to catch their own train.

There were plenty of enthusiasts on the platform to film and photograph the train’s departure from Brighton – bang on time.

Rather than spot numbers or trace the route of the journey on a track map, I chose instead to admire the view out of the window, speak to fellow passengers and recall the many journeys I have made on these trains both for leisure and for work.

I felt I knew every chain and every mile of the route from trips up to Three Bridges and beyond and across to Hastings in the east and Portsmouth in the west. Days out, holidays, business meetings – all conveyed by the coastway trains.

On board, I caught up with Chris Fowler, network operations director at Southern, who told me: “We are getting rid of the 313s and replacing them with Electrostars so that people get toilets and air-conditioning on these routes. They’ll be going in a couple of weeks’ time and we wanted to see them off in style, to commemorate the amount of service that they have given to this part of the country and to give people a good day out and to raise a lot of money for charity.”

A charity raffle was held to raise funds for the Railway Children charity and Chestnut Tree House children’s hospice care. I won a raffle prize! It was a book about ‘Isle of Wight: Past and Present’ which brought back memories of childhood (and adult) holidays by train to the island.

As I sipped from my flask of coffee, I bore in mind the stark warning about liquid intake knowing that there wouldn’t be a proper loo break until the lunch stop at Littlehampton three hours after departure.

Most of the other passengers – perhaps veterans of these railtours – seemed to have bought drinks before boarding or were absteeming.

At Portsmouth Harbour, there was just time to get a quick picture in front of one of the units (which then became the back end for the next leg) and a glance at HMS Victory before setting off once again.

Many of the people I spoke to on the journey to Littlehampton seemed to be in favour of the units being replaced. They wanted to be part of the railtour to see out the Class 313s and note the changing of the rolling stock.

One such was train aficionado and social media personality Francis Bourgeois.

He told me: “The 313s are very important to me as I used to get on them when I lived in Harlesden so I used to get on at Willesden Junction a lot to see them go by when I was younger. Happily with this unit I can see some of the old Silverlink colours flaking through the paintwork. It’s just nice to be on it and remember the journeys that I’ve been on with the 313s.”

I pity the poor staff at Littlehampton station. Never before have so many people jumped off a train and headed straight for the toilets on a Saturday lunchtime as when our charter pulled in for a refreshment – and toilet – break.

The queues wound out the door and well down the side of the platform. It was a relief for everyone!

After our break, there were a few minutes to spare before the service departed so I cheekily asked if I could look in the driver’s cab. Full credit here to the very helpful and obliging Southern staff: not only did I look in the cab but I had a chance to pretend that I was driving. Honestly guv, I didn’t touch nuffink!

The sun shone as the railtour whizzed along the West Coastway route to Hove then up to Three Bridges for another quick stop.

Here, the past met the future as a Thameslink Class 700 train passed by on the other platform showing how the design, look and comfort of trains have changed since the Class 313 units were first built in 1976/77.

So the tour continued with occasional stops, lots of people in the fields or on platforms to capture this farewell event and lots of memories of journeys made over the last 13 years on Southern 313 units.

It was a day for memories. It was a memorable day.

But also a reminder that our railways are in constant need of modernisation. What looked like the future in 1976 belongs to the past in 2023.

As for the units, they are being scrapped although there are plans to preserve one for the national railway collection. I wonder what future train travellers will make of the conditions we have endured on board these units for so many years in the first quarter of the 21st century.

They’ve served their time. Now their time is up. It is right they should be consigned to history.

I, for one, can’t wait to see the new rolling stock in place, safe in the knowledge that warnings about the lack of toilet facilities on these routes also belong to the past.

If you love these units and are sad to see them go, then hurry to catch them in the next few weeks before they become a museum piece.