There used to be a fenced pedestrian along the upriver side of the approach to the drawbridge at North Station. You walked onto (or maybe into) it from the parking lot of the Spaulding Rehab Center, which is next to the Suffolk County Jail. It was a great place to stand or sit during rush hour. Now, with the Downeaster, I imagine it's an even better place, if it's still there and still accessible. You could also see the East Cambridge Viaduct of the Green Line, and on a summer day, there were boats on the river, and the drawbridge opened and closed. You stood with the tracks right at eye level and had a great view of where the rails of the bridge met the rails on land. It was all perfectly legal and safe, with a good fence between you and the tracks; the only doubt I have is whether the railing on the river side was enough to keep a 2-year-old from falling into the Charles. Pretty easy train ride for you, too, depending on how easy it is to walk there from N. Station right now. I haven't been there in maybe 15 years, so I don't have any idea if you still can get to it, but it was such a great place that I've thought of going many times. The thing is, I live in Indiana now and only visit Boston for a week or so a year. If someone else knows if the walkway is still there, I'd love to know.