Which motor vehicle is not allowed to change gears while crossing uncontrolled railroad tracks?

When crossing uncontrolled railroad tracks, certain vehicles must adhere to specific safety regulations to ensure the safety of the occupants and others on the road. In this context, motor buses are typically not allowed to change gears while crossing these tracks due to their size, weight, and the potential safety concerns involved.

Changing gears can cause a vehicle to momentarily lose power, which could lead to a dangerous situation if the vehicle were to stall on the tracks. Motor buses, which are designed to carry a larger number of passengers, have stricter regulations around their operation, especially in critical situations like railroad crossings. Ensuring that the bus maintains a steady speed through the crossing minimizes the risk of stalling or experiencing mechanical issues at a potentially hazardous location.

On the other hand, smaller vehicles like passenger cars, pickup trucks, and large SUVs can maneuver more easily and are generally expected to navigate crossings with fewer regulations concerning gear changes as long as they approach the crossing safely. The guidelines focus on preventing accidents and ensuring the vehicles can clear the tracks efficiently when a train is approaching.