Applying a shunt is not fail-safe without verification by the dispatcher. One does not want emergency responders to place a shunt and think they had fulfilled their responsibility to stop train traffic. What if they adjacent to a non-signaled segment of track? Better yet, what if they are by a non-signaled segment of track near a crossing equipped with active warning devices? Seeing the warning devices operate would fool them into thinking approaching trains have been warned. What if they are by a signalized segment of track but they place the shunt after an approaching train has passed the last preceding block signal? What would the responders do if they see nearby warning devices equipped with predictors deploy and then "time out?"

It is far better for responders to use the phone numbers located at every crossing on the emergency notification sign along with the crossing number to properly locate their exact location. Railroads regularly provide training to emergency responders along their right of ways. While the focus is on haz mat or passenger emergency preparedness, training on how to contact the railroad is included. Having a dispatcher tell a crew to bring their train to a controlled stop is preferable to having a signal drop right in their face because someone suddenly dropped a shunt. A train draped over some vertical curves with loads and empties scattered throughout might not respond well.