It's crowded, your feet hurt, you're tired, there are no seats left and you're standing next to someone who has never heard of deodorant.
This is the experience of many people travelling to work every morning.
But things are quite different for a small group of commuters riding on the 7.18am from Eastbourne to London Bridge each day.
Regular users of the service will instantly know who they are - a group of 14 people who have found a way to beat the Monday morning blues.
In their own words, they're "mad, loud and boisterous". They are known as the Train Gang and their mission is to have fun.
Unsuspecting fellow travellers have found themselves dodging champagne corks, humming along with a singing fish and taking part in the gang's food tasting games.
Ganger Gary Shoesmith, a human resources manager, reckons it is good fun for everyone.
He said: "When you look up the train, people are always smiling. They love listening in and they never move away."
Another member of the gang, 33-year-old legal secretary Sue Welch, recalled how the group started when she overheard two other Train Gangers of the future, Nicki Welch and Angela Medrado, talking on the train about a holiday in Brazil.
Sue said: "I joined in the conversation. Nicki has the same surname as me but we're not related. Soon the three of us were out drinking and clubbing every Friday night. We started travelling home together and that's how the Train Gang was born."
Five years on, the group comprises six women and eight men, with ages ranging from 27 to 71.
Members include a company vice- president, an accountant, two engineers, a civil servant, a secretary, a human resources manager, a solicitor, management and property consultants and, perhaps fortuitously, a health and safety adviser.
Adrian Bloor, a 71-year-old property manager, had been travelling to London for 25 years before becoming the first man to be adopted by the gang. Now he is affectionately known as The Godfather.
Sue said: "He's the oldest and wisest member of the group but he's always willing to have fun. He keeps us all in line."
In true Train Gang style, Christmas carols, plenty of lights, lots of mince pies and a good measure of bubbly were the order of the day as the Christmas bash got under way.
Gary said: "We gave out mince pies to say thanks to all the people on the train who have put up with our noise this year."
New members are welcome but the group stresses that core members do have specific seating status and you could find yourself answering to Rosie and Bob, who get on at Plumpton, if you grab the wrong spot. But once you are in, you are in.
Nicki, a 39-year-old PA, said: "There have been many great journeys. The best was when the group took the early train to Gatwick to surprise our founding member, Angela Medrado.
"She had been in Brazil for several years and we surprised her at the airport with a welcome banner, a picnic breakfast, champagne, a limousine, coffee at the Grand Hotel and lunch at the local marina. It reminds me of the special relationships that have been made here."
Sue said: "I don't think I could do this journey now without the gang. I've made friends for life here."
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