When two railroads, a railroad and an interurban railroad or electric or street railway, two interurban railroads, or a railroad or electric railway and a street or highway cross at grade, if, in the opinion of the public utilities commission, public safety requires protection, the commission, upon its own motion or upon complaint, after notice to the railroads interested and full investigation, may make an order requiring the railroads so intersecting and crossing to install such devices as in the opinion of the commission will properly protect such crossing.

The commission may make any other orders regulating the speed and running of trains or of cars and the switching of cars over such crossing or street, and it shall apportion the expense of installation or maintenance of such devices between the railroad companies whose tracks are thus protected.