I remember this series. It was (very) loosely based on the London Underground here in Britain, with most of the trains being named after lines on the system. (Circle, Victoria, Bakerloo, Jubilee, and Hammersmith and City.) There were also trains from other underground systems, named after the city that served them. (Sydney, Moscow, Paris, Brooklyn, etc)
The 'Circle' set was released around 2009, as an alternative to Bachmann's 'Junior' range, with the other trains available in 2-car packs. There was also an accessory pack based on the central station in the series, along with another destination that I can't remember the name of. (Mystery Mansion, I think.)
Hope this helps, as at this point my memory is fried after extracting all of this from it.
The 'Circle' set was released around 2009, as an alternative to Bachmann's 'Junior' range, with the other trains available in 2-car packs. There was also an accessory pack based on the central station in the series, along with another destination that I can't remember the name of. (Mystery Mansion, I think.)
Hope this helps, as at this point my memory is fried after extracting all of this from it.
Collecting without a clue since 2010