Appropriately enough, who should break into his reverie but a couple of boys, estimated by Mr Kirk as being "around Year 7 and Year 8" and in chattier mood than he might have preferred.
"Hey mister," confides boy one, pointing to a female passenger sitting nearby: "Isn't that Nightshade of the Gladiators over there?" A moment's examination satisfies man and boy that, indeed, it was. A pause. The child turns his attention to Mr Kirk. "Are you a Gladiator?" Here the youngster's motives (or eyesight) become a trifle unclear, for while Mr Kirk is a keen rambler with his greying beard he is unlikely to be mistaken for Mr Motivator. Mr Kirk replies that he is not, in tones intended to signal the ending of the conversation.
But the urchin pipes up once more: "'Ere, mister, I'm famous. I've been expelled from five or six schools." Not to be outdone, his previously silent brother adds: "I'm famous, but not as much as him because I've only been expelled from one school."
Had Mr Kirk actually been a Gladiator at this point, his stage name might appropriately have been Gobsmacked.
In this Blairite age, it is perhaps fitting that the humorous acceptable face of trade unionism now exists.
John Monks, general secretary of the Trades Union Congress, made this clear in his speech to the Association of Teachers and Lecturers conference a couple of weeks ago.
Extolling the virtues of training he cited the case of a novice news reader who was given the latest tennis results to read. The poor chap told surprised listeners that "Steffi Graf had beaten Gabriel Sabatini six minus four; three minus six and seven minus five".
But a little training was worse than none at all, Mr Monks continued, piling on the agony. Another hapless sports announcer was told of the importance of raising the voice when giving the name of the winner and lowering it for the losing team. He proceeded to announce: "Football League: Division one, Arsenal nil," and continued in similar vein. Some five minutes later, much to his consternation, he discovered he had one team left over.
Conference season is not only the time for recycling militancy, but also for the retelling of anecdotes.
Gillian Shephard recounted the same story to the Association of Teachers and Lecturers and the National Confederation of Parent Teacher Associations.
It goes: A young man in his first teaching job had the temerity to reprimand a pupil. The pupil took umbrage and threatened him with his dad, a boxing champion. As the day wore on, the rumour spread throughout the school so, when a huge shadow appeared in the frosted glass of the classroom door, the teacher prepared himself for the worst and the class awaited his fate with eager anticipation.
The shadow manifested itself and asked: "Are you Mr Humphrey?" "Yes," came the nervous reply. "Good," said the hulk. "I've come to read the meter."
Desperate press release of the week: received from City and Guilds and helpfully pointing out that a Coronation Street character - trainee hairdresser Fiona Middleton - had proudly taken delivery of a National Vocational Qualification certificate for crimping.
It continues by quoting Dr Nick Carey, director-general of City and Guilds, saying: "This is really good news. . . clearly NVQs are now the accepted indicators of occupational competence."
Perhaps when Bet Gilroy gets NVQd for pulling pints, Jack Duckworth is certificated for first-class skiving and Ken Barlow's Boring for Britain earns him a vocational qualification, viewers will indeed sit up and take notice.
Congratulations to John Andrews, general secretary of that strike-free zone, the Professional Association of Teachers, who has at a stroke upped his membership by some 10 per cent.
PAT has, you see, annexed the Professional Association of Nursery Nurses (another strike-free zone of some 4,000 souls) partly fathered by Mr Andrews in the early 1980s. A press release crows that "a massive 85.5 per cent" of those who voted were in favour of PANN becoming a section of PAT.
However, it transpires that turnout was well under half at 44 per cent, meaning that around 1,800 members actually voted in favour of this brave new move.
One thing baffles us: Mr Andrews is quoted as saying that "PAT, with the new PANN section, will be able to ensure that more children are protected by the no-strike commitment." Um. . . since both organisations already eschew strikes, surely numbers of "protected children" will remain exactly the same?
Nigel de Gruchy, gauleiter of NASUWT, is known as a man of moderate tastes. But a recent trip to Russia could change all that. At one business meeting, the vodka bottle came out - containing that clear substance which previously has not been Mr de G's tipple of choice. "It tasted a lot better when drunk with caviar," he enthused.