Under the letter B have been classed considerations of maintenance and
construction.

9. Protection, more or less complete, of the machinery against the
action of dust and mud.
10. Regularity and smoothness of motion.
11. Capacity for passing over curves of small radius.
12. The simplest and most rational construction.
13. Facility for inspecting and cleaning the interior of the boilers.
14. Dead weight of the train compared with the number of places.
15. Effective power of traction when the carriages are completely full.
16. Rapidity with which the motor can be taken out of the shed and
made ready for running.
17. The longest daily service without stops other than those
compatible with the requirements of the service.
18. Cost of maintenance per kilometer. (It was assumed, for the
purposes of this sub-heading, that the motor or carriage which
gave the best results under the conditions relating to
paragraphs 9, 10, 12, and 13 would be least costly for repairs.)

As regards the first of these, viz., protection of the machinery against
dirt, the machinery of the electrical car had no protection. It was not
found in the experiments at Antwerp that inconvenience resulted from
this; but it is a question whether in very dusty localities, and
especially in a locality where there is metallic dust, the absence of
protection might not entail serious difficulties, and even cause the
destruction of parts of the machinery.

In respect to the smoothness of motion and facility of passing curves,
the cars did not present vary material differences, except that the cars
in which the motor formed part of the car had the preference.

In the case of simplicity of construction, it is evident that the
simplest and most rational construction is that of a car which depends on
itself for its movement, which can move in either direction with equal
facility, which can be applied to any existing tramway without expense
for altering the road, and the use of which will not throw out of
employment vehicles already used on the lines; the electric car fulfilled
this condition best, as also the condition numbered 13, as it possessed
no boiler.

In respect to No. 14, viz., the ratio of the dead weight of the train to
passengers, if we assume 154 lb. as the average weight per passenger, the
following is the result in respect of the three cars in which t