Aldershot is there because it’s Via trying to serve Hamilton, not Burlington. Hamilton just doesn’t have a train station on the line.
Indeed, VIA consolidated its existing stations at Hamilton, Dundas and Burlington at Aldershot on May 25, 1992.
Just a short operational history of these 4 stations:
Hamilton
Hamilton's CN Station at James Street North was used by almost all its Toronto-Brantford-London trains until April 1962:
Source: CN timetable effective 1961-10-29
On April 29, 1962, all such trains dropped Hamilton as a stop (thus saving approximately 20 minutes in travel time), except for
eastbound westbound trains 77 (the morning Toronto-London train), 9 (the Toronto-Windsor night train) and 15 (the Toronto-Chicago night train called "International Ltd."):
Source: CN timetable effective 1962-04-29
Train 77 had its last scheduled run on December 31, 1964, the "International Ltd." its last scheduled stop in Hamilton on October 29, 1966 and the night train Toronto-Windsor ceased operation on June 30, 1967.
Nevertheless, the Toronto-Niagara Falls service continued to serve Hamilton until April 24, 1992:
Source: VIA timetable effective 1992-04-26
Dundas
Dundas had always been a minor stop for CN, but initially, they tried to ensure connectivity between London and Hamilton, by
rerouting terminating its Niagara-Toronto services
via at Dundas
(the schedule indeed seems to suggest that the RDCs from Niagara-Hamilton were attached to London-Toronto trains, but the fact that they arrived only a few minutes before they returned towards Niagara suggests otherwise):
Source: CN timetable effective 1962-04-29
However, within months that experiment was dropped in favor of having passengers connect at Burlington or running a connecting bus between Hamilton and Dundas. VIA inherited that connecting bus service to selected departures of the Toronto-London service and rerouted it first to Brantford (in April 1977) and soon after to Burlington (in October 1978), before discontinuing it in November 1987.
Nevertheless, the stop at Dundas survived until May 24, 1992:
Source: VIA timetable effective 1992-04-26
Burlington
Most, though not all CN services stopped at Burlington and VIA continued to do so until May 24, 1992.
Aldershot
Aldershot was only used by 1-2 of CN's Hamilton-Toronto commuter trains until the stop disappeared with the timetable change on 1965-10-31 (after which the station was not used by any intercity trains until VIA decided to consolidate its Burlington/Hamilton/Dundas stops on May 25, 1992 at GO’s new station which had been built approximately 0.3 miles East of the old location):
Source: CN timetable effective 1965-04-25
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With all of that said, I can see VIA returning to stop at GO's West Harbour Station, but only if CN allows GO to build a connection from GO's platforms to its main tracks (which would shave quite a few minutes off GO's weekday commuter service from/to Niagara Falls) and obviously only for the Maple Leaf, as for Toronto-London-Windsor trains, the penalty of going via Hamilton will always be too much of an inconvenience. This is why I struggle to imagine that they would move their stop back to Burlington, as it would be quite a bit further from Hamilton, but in the end, Hamilton is located at the wrong rail corridor...