[Illustration:  FIG. 2.]

The secondary railways in rural districts in Austria having no gates or bars at the level crossings, or guards at such points, but being open like tramways, special precautions are required to avoid accidents, and the public has to be warned of the approach of the train from a sufficient distance.  This is done by ringing bells preferably to sounding whistles, as these are more likely to startle horses.  The steam bell shown by our illustrations has been adopted for this purpose on the Austrian lines, and is a simple contrivance.  It consists of a cylindrical chamber, a, ending in a narrower tube, c, which forms the seating for a flap valve, d, to which the hammer or clapper, e, is fixed.  Steam is admitted through a small pipe, b, at the bottom, and after a certain interval attains sufficient pressure to lift the valve.  The opening being large compared with the pipe, b, steam escapes more rapidly than it arrives through the small orifice; the pressure falls, and the valve drops down and causes the hammer to strike a bell surrounding the cylinder.  The valve is provided with an internal collar as shown, so that it has to rise for the width of this before the steam is let out, and thus determines the swing of the clapper and the force of the blow.  To intensify the latter and multiply the number of blows, the clapper spring is prolonged over the fulcrum and bent back so as to form a spring, which is tightened by the lifting of the flap, and sends the clapper down on the bell with increased force.  The hinge of the flap does not require any lubrication besides what it gets through the steam.  The bell is fixed upon the roof of the driver’s cab, so that the steam does not interfere with his lookout, and fastened by three bolts or screws.  The diameter of the steam-pipe is from 1/4 to 1/2 inch according to the size of the bell, and the distance of the clapper from the bell is a little less than the diameter of the corresponding cock.  The steam cock is perforated as shown by the illustration to drain the pipe when shut, and a small hole, b, in the bell cylinder drains the latter.  The steam-pipe is made with a bend as usual, to allow for contraction and expansion.  The number of blows given varies according to the steam pressure, and the opening of the steam cock; it is

With 90 lb. pressure, and cock 1/2 open, 170 blows per min.
      " " " " 1/3 " 136 "
     105 " " " 1/2 " 240 "
      " " " " 1/3 " 156 "
      " " " " 1/5 " 136 "
     120 " " " 1/3 " 228 "
     135 " " " 1/5 " 200 "

To start the bell, the cock is opened full, and afterward partly closed.  The blows follow in such rapid succession that a kind of uniform sound with louder intervals is produced, but not of the same shrill character as by a steam whistle.  The same kind of bell is used on the shunting engines in goods yards, where roadways have to be crossed on which lurries and handtrucks circulate, and the results as far as prevention of accidents is concerned are stated to be very satisfactory.