An outside party can apply to the STB to force an abandonment - this is called an "adverse abandonment." It is often seen where a government agency (or private company) wants a rail line abandoned so the right-of-way can be converted to their own use.

The STB allows common carrier service to be "discontinued", which does not allow abandonment. I don't know if there is such a thing as an "adverse discontinuance."

A railroad can also embargo service, due to track/bridge/tunnel conditions or even congestion. This is only allowed as a temporary status, and connot be indefinate if service is being requested.

My GUESS - they might embargo freight traffic to allow SMART construction, but would likely compensate affected customers for transloading or trucking costs, possibly cheaper than keeping the line open for freight during construction.