Incidents like this help justify the need for tighter security around railroad facillities in the US.

They'll prompt railroad and transit police to take a closer look at people taking pictures around stations and track even in public areas and give them a reason/excuse to stop and question you maybe even examine the pictures you've taken.

I suspect that domestic and international terrorists have figured out how vulnerable our transit systems are compared to airports and other "hardened targets" like government buildings that have better security than the railroads.

Some have probably scouted major US stations looking for vulnerablity

We're very fortunate that there has not been a successful attack on board a train in the US.

If it ever happens here US railroad stations in major cities could be subject to the same level of boarding security at airports including mandatory screening before getting to the
platforms and other inconveniences like locked bathrooms and removal of trash cans... It's already in place at lots of subway stations.