If that happens, it will be beneficial for valley residents and people of Jammu required to visit their state's summer capital. Even for direct train places like Delhi, I guess the authorities could have secured the station at Srinagar (only Srinagar in the valley at least) like they do at Srinagar airport, having multiple layers of security.
IMO, govt might think of such a plan soon, once the SINA-SVDK/JAT section is operationalised.