So who would you vote off first," asked Mark, "mobile man or hummer?"

"Hummer, I think," I replied. "Or maybe mobile man, I'm not sure ..."

"You must make your decision," said Mark. "Oxygen is running out."

This is Mark's latest way of passing the time, when stuck at signals or points, or because there are no drivers, or whatever the reason for sitting on a train going nowhere happens to be.

The scenario, largely adapted from TV game shows like Survivor and Big Brother, is that we are stuck on the train, in sweltering heat, in an extremely overcrowded carriage (all of the above being true) and - and this is where the game kicks in - the oxygen supplies are rapidly diminishing and in order to survive the journey you have to vote one person in the carriage off the train.

The longer the delay, the more passengers get shown the door.

"So who is it to be, mobile phone man or hummer?"

Mobile phone man has, ever since the train stopped 20 minutes ago, been phoning everyone he can think of to tell them his train is delayed and he may be late for the meeting.

Hummer is possibly even more irritating but also rather more weird and therefore don't feel entirely happy about evicting her.

She came to our attention a few days ago when I was listening to David Copperfield (the Dickens version rather than the magician) on walkman (as advised in how to beat stress of commuting article on net) when I noticed a strange buzzing in headphones.

Having failed to stop it by shaking, tapping and switching the walkman on and off, I turned it off altogether, only to find that the buzzing continued.

"What's that noise?" I asked friend Sarah. "Her," she said, seething and nodding in direction of rainbow-shirted woman who was sitting very straight-backed with her eyes closed and humming.

While Sarah was annoyed, I was slightly concerned that she might be distressed or unwell or even in the first stages of labour. "Do you think she's all right?" I asked Sarah, who suggested that I ask her.

"Never better," said hummer, smiling serenely. "I'm practising a form of meditation, as a way of beating the frustration caused by this train being delayed. The chanting helps block out negative stress rising in the rest of the carriage."

She smiled again and returned to her "Mmmmmmm, Hmmmmmm" while the negative stress of the carriage rose further still, in relation to her mmms and hmmms rather than the guard's cheerful announcement that he had no idea why we were sitting in a field outside Balcombe in temperatures of 80 degrees but would let us know as soon as he did.

"I suppose mobile man is using more oxygen, so I'll I think he should go first," I finally told Mark and immediately became worried that he had overheard as phone went quiet and all you could hear in carriage was humming.

Then he piped up again. This time he was not talking to anyone on the phone but someone in the carriage. "Excuse me," we heard him say. "But would you mind stopping that ridiculous noise. I'm trying to sort out some business and finding it extremely off-putting."

"But I," said hummer, "am trying to focus my thoughts for the day ahead, and am finding your talk of sales targets and performance enhancing strategies extremely off-putting ..."

"I think we should keep them both," Mark decided. "It makes the journey more interesting."