Kelso Conservation Area, west of Milton, is a good place for the family, with good access to the tracks. The latter is run by the Ontario Southland Railway, whose vintage Alco power ties up at the Junction. Guelph Jct is also the terminus for GO Transit trains, which deadhead to and from Milton for their runs to Toronto. The Galt Sub is a very busy line from Lambton westwards. Trains run between Union and Milton on weekdays.
Sub carry their westbound numbers.
Hamilton Yard 39.3 Hamilton The Oakville Subdivision, CN's original east-west mainline, runs south of the Queen Elizabeth Way from Toronto all the way to Bayview Jct in Hamilton. There are plenty of places to access the tracks. The right of way is straight and open, making photography easy, but the surroundings are pretty mundane. The area close to Aldershot is still fairly natural, but otherwise count on suburbs and industrial areas all along the right of way. Sub is mostly three or four tracks.