It’s pretty unusual to be hired directly as a train driver (or Locomotive Engineer) into major Canadian firms, Canadian National & Canadian Pacific (the two largest freight carriers with crew based nationwide) require people to join as Conductors first and be promoted, as do GO Transit and many smaller railways. VIA Rail (AAIU), much like Eurostar in the UK, only take already qualified Locomotive Engineers from elsewhere.
On the metro side in Toronto you can be hired directly as a Subway Operator with the TTC, but the only possible way to apply is as a General Transit Operator, from which one could be streamed into Bus, Streetcar or Subway Operator. It is possible to move between different streams but that takes years to arrange, and as I understand it subway is the most sought after section of the Commission (although new hires have been assigned Subway straight away quite frequently in the past)
In Montréal you have to have been an STM bus driver for at least 5 years to have a sniff at the metro, and to be an STM bus driver you have to speak fluent French.
That’s all pretty negative I know, but on the positive side seniority lead in times for a Locomotive Engineer are anecdotally fairly short, so you could be on a course in a single figure number of years, perhaps even towards the lower end of that. Pay is typically around the $110,000 mark per year for a L/E, perhaps more. Conditions are (especially on the freight side) less than fantastic, oftentimes at the lower end of seniority (the railways in Canada usually operate on seniority, for reasons best known to themselves) engineers and conductors are on a 24 hour on call with 2 hours notice, which is obviously pretty grim. Lodge turns (overnight trips away) are endemic.
The other problem is without at least Permanent Resident card the major firms won’t look at you (though some smaller companies will). Once you’ve got that it’s a question of checking the job sites of the major companies and applying for vacancies. CN and CP in particular are hiring for conductors almost continuously so there isn’t an issue jobs wise (although it can be a problem finding a job in some sought after/low traffic locations, the Maritimes for instance)
Above all good luck, hope that helps