And there are no tales of a misspent youth standing on windy platforms collecting train numbers. He did use to commute by train from his Dulwich home to his office overlooking St James's Park, but now, since taking charge of the formation of Britain's new railway companies, he gets a ride in a chauffeur-driven government car.
"It saves me nearly an hour a day, and I can work and make phone calls. I already leave as early as 7.30am, and rarely get home before 8pm. It's long enough, and the train would take longer," he says without a hint of sheepishness.
Mr Salmon is a merchant banker. He has previously worked as an adviser for TML, which built the Channel Tunnel, and on the Docklands Light Railway, but admits that he knew little about the railway before starting.
He spent 17 years with NM Rothschild specialising in "putting together complex multi-party transactions".
He was head-hunted for the job, which he took up two years ago, and he feels his experience at Rothschild's has been invaluable: "I have to put together deals with ROSCOs [rolling stock companies], TOCs [train operating companies] , the Government, and a lot of people indirectly, to create a franchise that will be sold off as a business."
Mr Salmon's official title is director of the Office of Passenger Rail Franchising (OPRAF), but, in effect, he has power of life and death over the railways, and already, before a single pound of private investment has been attracted into the railways, the casualties have begun.
His first task is to set out the passenger service requirements for the 25 franchise areas that have been carved out of the rail map, and in publishing details for the first four, he has not included some routes such as InterCity trains from Paddington to Carmarthen and Fishguard.
He has also announced that he will not be including Motorail, or the sleeper service to Fort William in the Scottish Highlands.
The latter decision has provoked a powerful campaign by Scottish local authorities, peers and some senior cabinet ministers to retain a service seen as vitally important to a fragile local economy which is heavily dependent on tourism.
Last week Mr Salmon's office hit back by disclosing that the line costs £450 in subsidy for every person who uses it. He does accept, however, that the task of determining which heavily subsidised lines should close is an "onerous responsibility".
The Transport Secretary has the power to instruct him to pay subsidy for a particular service, but he feels that the Government will let him make the decisions.
Mr Salmon is charged with allocating the subsidy - expected to be around £1.6bn for the year starting on 1 April - to the train-operating companies to pay for loss-making services. Under the new financial regime of the railways, virtually all services - with the possible exception of Gatwick Express - are loss-making.
Mr Salmon's initial minimum timetables for the first four franchises - Gatwick Express, London Tilbury and Southend, South West Trains and Great Western - have fewer trains than existing timetables.
For instance, there are only two trains per hour on the Gatwick Express rather than four, but Mr Salmon is confident that "if there is a commercial incentive, these extra will continue to be operated".
He feels that if he had specified the existing levels of trains, franchise bidders would have demanded more subsidy than on those reduced: "We would have had to pay more for such inflexibility and I don't think that would have been worth it. I will get more attractive bidders, if they have flexibility."
Does that mean these trains may be cut one day? "Operators want the right to be able to offer fewer trains if life gets tough and there is a recession."
While such logic may be correct, it leaves the public bemused and fearful for its train services.
Does Mr Salmon, therefore, see himself as a second Dr Beeching? - the man who took his celebrated axe to Britain's rail network in the Sixties.
"Certainly not. What I am doing is putting in contractual protection for the first time ever for train services. I have a duty to procure good services and value for money."
Mr Salmon earns £102,750 a year for what is nominally a four-day week - "I wanted to keep the right to do other things but at the moment I'm working most of the time for OPRAF" - and reckons he "could earn a great deal more" back in the City.
He will give evidence on Wednesday to the Commons Transport Committee, which has set itself the difficult task of examining railway finances. He faces a tough jobReuse content