502 report— 1879. 



■without fire, that is to say, by means of hot water heated to a high temperature- 

 by the injection of the steam into a body of water. 



He made a very successful application of his system on the line of tramways^ 

 between Rueil and Marly le Roi, near Paris, which is in a working order since' 

 the month of July of the last year, and never failed nor gave any reason of 

 complaint from the public. 



The principal object, namely, the suppression of the furnace of the locomotive, is 

 obtained by the utilisation of the calorific capacity of water, by giving it a quantity 

 of heat sufficient for the production of the steam necessary for the working of 

 each machine during a good length of time. The means adopted consists in 

 causing to pass into a volume of water contained in a closed reservoir placed 

 on the locomotive, a current of steam at high pressure produced in a generator 

 fixed at the departure station, and which - gives up its heat iu the ratio of its 

 mixture with the water. 



The locomotive consists of a large cylindrical reservoir, surmounted by a 

 dome in which the steam is accumulated, and supported by a frame to which 

 are fixed all the mechanical movements similar to those of an ordinary loco- 

 motive. 



The reservoir holds more than 700 gallons, about two tons of water, which,, 

 introduced into the apparatus, should be heated to a very high temperature before 

 the locomotive is put in motion. By the aid of a fixed generator, it is capable of 

 producing steam at a pressure which may attain sixteen atmospheres (224 pounds 

 per square inch), at a temperature of 203° Centigrade. 



The steam comes from the generator into the reservoir by a pipe forming 

 a branch with another horizontal pipe placed near the bottom of the reservoir 

 along all its length, closed at its two extremities, but pierced on its upper surface- 

 with two lines of small holes. 



The steam rushing from the generator escapes through all the holes of that 

 tube and brings the water of the reservoir to the desired conditions of temperature 

 and pressure. 



The distribution of steam to the cylinders of the locomotive is not different' 

 from similar machines except in its mode of working. The escaped steam is not 

 used to increase the draught, as there is no fire; it forms no clouds of steam 

 issuing from the chimney, and produces no noise in escaping. 



The escape is made into an air condenser, formed by a close cylinder traversed 

 by more than 600 metallic tubes which are open at both ends, so that the ah may 

 pass freely through them from end to end and keep them cool. The steam 

 after its working is condensed into that cylinder, and the water falls into a, 

 small tank placed under the foot-board of the driver. 



The principal apparatus of the tireless engine invented by Mons, Francq is the 

 expansive regulator (detendeur), by which the steam is carried to the cylinders of 

 the locomotive regularly and at the same pressure. 



That pressure may vary from three to eight atmospheres, according to the 

 amount of resistance of the cars running on the tramways. 



The spring of a balance, similar to those used for safety valves on boilers, is 

 applied for opening more or less the valve of admission of the steam into the 

 exhaust regulator, and it acts so well that while the locomotive is in work the 

 valve of admission oscillates in almost precise correspondence with the pulsations 

 even of the motive pistons. 



The traffic on Reuil and Marly Railway having been carried on by small 

 locomotives of the ordinary type previous to being worked by tireless engines, 

 affords an opportunity of making an exact comparison between them. In regard 

 to consumption of fuel, the account shows an important advantage in favour of 

 the tireless engine. The boiler of a locomotive is much more expensive on account 

 of its brass tubes in construction and in maintenance. 



The books of the company prove that the ordinary locomotive costs 41 francs 

 39 cents, and the tireless engine only 22 francs 77 cents, nearly the half, for a run 

 of 102 kilometres every day. 



The tubes in the boiler of the ordinary locomotive last six or seven years, and 



