The CONDUCTOR does not have to stop. They are just one of the crew on the train.
They DO NOT have to call police.
The Engineer will in most cases stop the train. The crew members can call who they like for assistance to get the train moving again.
The railroad has its own Police Service if they think they need them.
It is not train crews job to pick up body parts or untangle wreckage.
It is not train crews job to contact family members to come fetch the leftovers.
Train dispatcher can contact appropriate local personal to assist in getting the train moving.
That might be local or state Police, Local Ambulance or Fire service. A Local Crane,a railroad crane, Maybe some electricians to repair gates or signals maybe even NTSB or some part of Homeland security maybe you are a terrorist trying to do damage to the rail system . Not the train crews job to figure it out.
The irritant of you smeared on the train parts is usually handled with a Fire Hose.
Railroad in most places is not under the Highway traffic rules.
It is under Railroad rules.They are FEDERAL Laws.
Which part of Right of Way do you not understand?
If the train is on the tracks it is where it is supposed to be.
YOU can call police if you want after an accident. Probably a better idea to call an ambulance and fire rescue services.
This theoretical problem is not something you need to worry about if you stay out of the trains way.
If you are lucky maybe someone will take a video of your parts that they can give your family or post online for everyone to enjoy,
Many videos on line if you want to see them. Most require you to be 18 to view them.
https://www.youtube.com/watch?v=vc-8rZPk6-A
If it is an electrically powered train they may need to wait to help you while electricity is shut off.
POLICE do not shut off the electricity.
Sometimes Police are already there and do not need to be called.
https://www.youtube.com/watch?v=7YJfMr5OOuY