^ Dweebe, I'm assuming for item 2 that you are actually referring to the UP freight line not metrolink.
My personal experience is prior to meeting my wife and moving to St Louis is that I owned a townhouse in Lisle, IL (Chicago West Suburb). The townhouse complex was literally next to the BNSF three track Aurora mainline that not only hosted significant amount of BNSF freight trains but also multiple Metra trains. My response would be that you can design and build to buffer against sound intrusions. Second, my neighbors we commuters and I think they appreciate the proximity to the Lisle Metra station more than anything. Especially in winter.
On a different note but along similar lines. I think the small commercial area across from the mini on the other side of Hanley would be a good place for townhomes or mulitfamily. Move the businesses into Sunnen Business Park. Yes, it would be also in a wedge up against the UP train tracks. However, it is on the same side of the street as the great little space ship park (what my boy would call it), a small local tavern/grill as well as easy access to future greenway without ever having to cross Hanley. At the same time, it would be a short walk over to the Sunnen metrolink station.
Which comes back to Maplewood itself. For all the great things you can say about revitalizing the downtown. They are also squandering the opportunity, with both Manchester and Sunnen metrolink stations, to build up residential density, demographics from families to senior living. Maybe they will get past the almighty sales tax mentality.