It the suburban area of a metropolis is huge, then that's one thing in terms of adding multiple stations in that area. For example, for Amtrak trains involving Upstate NY in their journeys-they pass through all of the Hudson River Towns in Westchester County but there are two stations in that county along the Hudson-Yonkers and Croton Harmon. Yonkers is more of a city station but surrounding it, there are many suburbanlike communities(Bronxville, and believe it or not, Riverdale, located in the Bronx). Mainly, regional trains stop at Yonkers. Further north along the Hudson but still in Westchester County is Croton Harmon which is mainly just a park n ride lot. It's not that accessible to major highways. The closest ones are 287/87 which are a little further down in Tarrytown and then you have to take Rt. 9D, I think. Croton Harmon is pretty close to a lot of other towns in Westchester County and it's not terribly far from Rockland County either. Just about every Amtrak train stops at CRT including 49 and 48.
in general, Amtrak doesn't need to have multiple stations within major city limits unless if the cities are huge and the main commercial areas go on and on. For example, it's fine that Boston has two NEC stations given the fact that there is a lot of commercial development that continues for a bit. In Los Angeles, north of LAUS, the Amtrak Pacific Surfliner and Coast Starlight route may leave the City of LA for a little bit running through Glendale and Burbank but then it enters the City of LA again stopping at Van Nuys(both Pacific Surfliner and Coast Starlight). The westernmost station in LA on Amtrak is Chatsworth, only served by Pacific Surfliner trains. Chatsworth is still several miles from Downtown LA.
in general, Amtrak doesn't need to have multiple stations within major city limits unless if the cities are huge and the main commercial areas go on and on. For example, it's fine that Boston has two NEC stations given the fact that there is a lot of commercial development that continues for a bit. In Los Angeles, north of LAUS, the Amtrak Pacific Surfliner and Coast Starlight route may leave the City of LA for a little bit running through Glendale and Burbank but then it enters the City of LA again stopping at Van Nuys(both Pacific Surfliner and Coast Starlight). The westernmost station in LA on Amtrak is Chatsworth, only served by Pacific Surfliner trains. Chatsworth is still several miles from Downtown LA.