FIRE LESS LOCOMOTIVE.

23

always^ S °. me ^ ow come to prevail that the big wheels of a locomotivePression 6 *^ 1 ' 116 wlleels t0 guide them. One of the reasons for this im~wheel n ^ r .°^ )a ^ > ^y t ^ le almost universal practice of making the fronta matter ? rC ^ nai 7 wa gons and carriages smaller than the hind ones. Aswich ^ ° ^ aCt ’ ^ ' S ^ ounc ' t ^ at H ie engines at present used on the Green-them S ^ ne run aroun d curves with all the ease that is required ofb een . e ^ an g e s of their wheels are not injuriously worn, and they haveof y C ° nsic ^ ere d sa fe in running around the curves on that road, which arelines r ^ mUcfl shorter radius than any that are proposed for the projectedengi W Ch are com Pl etec l- It therefore may be concluded that anyMV// 1165 W ^’ C ^ ‘ n t h's respect will do as well as those referred to will doIt can °u^ 1 ' anC ^ no ascfnl end would be attained by having them do better,stand to rea< ^^ shown that the angle at which the wheels of an engineof the ° t, ' le ra * 1S * S dependent u Pon the length of wheel-base. Thatif i t 6 en S ines at present used on the Greenwich street road is 5 ft. ; andsix-wlf 11 S ^ 0Wn Ihat the angle at which the driving-wheels of thedrive ^ eil H^ ne stand to the rail, when the engine runs with theit Wil^f 3 * 16 ^’ ' S 00 gTeater than that due to a wheel-base of 5 ft., thenthe fou° ° W tllat the six-wheel engine will run around curves as easily a swich ° Ur ' wheel - To do this apian of the running gear of the Green-s reet road engines, on a curve of 90 ft. radius, is given. The

Wheel Locomotive (Greenwich St. Road). Scale, \in. = i ft. Weight , n, 000 lbs.

an gle of the wheels in this case is half that measured by the arc a cof which the wheel-base is the chord. The running-gear of the six-wheelen gine is also shown on a curve of the same radius. In this case thedriving-wheels can assume a position on the track quite independentlyof the truck-wheels, because the centre-pin A is attached to a swingmotion on the truck, and can swing freely crosswise to the track ; sothat the position of the driving-wheels «, b, c, d is not controlled bythat of the truck-wheels. As the driving-wheel base is the same ineach engine, therefore the angle of the wheels to the track m bothca ses is equal to half that measured by an arc a c, whose chord is5 ft. ; therefore the six-wheel engine will run on a curved track withthe wheels c d in front as easily as the- four-wheeled engines daJt is true that by a proper adjustment of the connectmg-pm B,ar ound which the truck turns, the centre-line of the truck-axle may bemade to assume a position more nearly radial to the curve, and inwh ich the wheels will be nearer to being parallel with the track than isPossible for the driving-wheels when arranged as proposed, or as they arenow arranged on the engines on the Greenwich street road. What is con-tended for is that a six-wheel engine arranged as above will run ineither direction on curves as easily as the four-wheel engines now do,and that for all practical purposes that is easy enough.

The

writer, in order to test this question, had a model of the runnmg-

1 7 j. kle then

gear of the six-wheel engine constructed on a sca ^ was £ nC pmed. At the

had a track laid consisting of a straight piece c j rc l e> corresponding in

foot of this was a curved track of a quarter 0 >

placed on the

scale to one of 90 ft. radius. The model engin ®^ aS by its own gravity,incline, in a given position, and allowed to run amount 0 f momentum,In descending the incline it acquired a certan £y p£ ac ing the

which caused it to run some distance on the eve _ receive the sameengine in the same position on the incline it wou be curve indicated

amount of momentum, and the distance it wou r •„ there ; so that

the amount of resistance the model encountere in on the incline, it

by reversing its position, and placing it at the sam l ^ w £q c h direction itcould be known, by the distance it ran on the cur ^ thoroughly, it wasencountered the most resistance. After testing 1 v w i t h the truck-

found that it made no material difference whether

wheels or the driving-wheels in front. tbat engines of the

The conclusion from this, it is thought, mus be used, well

kind described will run around the shortest curves, w eConom y in secur-enough for all practical purposes ; that there would be^i . ^ ^ , { the ex .

mg more perfect theoretical working in this res P e ^ w p e els guide

pense of engines is increased in order always to iav ^ which has nothe big ones,” it will be expended for an idea or t eopractical value or importance.

The idea, however, that there must be little wheels at each end of theengine to guide it into curves carried the day, and all the locomotivesordered for that road were built in that way. Since then, however, themanagement of that road was changed and the present General Manager,Mr. Hain, saw the futility of using the extra pair of wheels in front, andas an experiment, removed them from one engine. It was soon found thatnot only would it curve better, but it would pull considerably more, andwould start trains quicker from stations, an important feature in engineswhich make as many stops as are made on the elevated roads. So success-ful was the experiment that the front pair of wheels on nearly all theengines on the line have now been removed, thus confirming the theory setforth in the pamphlet quoted from, which, if it had been comprehendedand acted upon, would have saved the company thousands of dollars forthe cost of the extra trucks under these engines, which were not only use-less but really diminished the efficiency of the engines.

The following are the dimensions of the first engines of this kindwhich were built:

Diameter of cylinders,

Length of stroke,

Diameter of driving-wheels,

Diameter of truck-wheels,

Total wheel-base,

Material of boilerNumber of flues,

Diameter of flues,

Length of flues,

Size of fire-box, -Diameter of axles,

Capacity of tank,

Weight of engine loaded,

Weight on driving-wheels,

Those which were ordered last have larger boilers, and the cab ismade shorter than that represented in the engraving, so that the water-tank and part of the boiler are exposed to view.

10

16

in.

in.

in.

in.

3928

15 ft. 6 in.Steel.

125.1 >4 in.70 in.in. x 27 in.

4 >4 in-320 galls.

32.500 lbs.

27.500 lbs.

SCHEFFLER'S FIRELESS LOCOMOTIVE FOR STREET

RAILROADS.

Fig. HO.

For several years experiments were made on the street railroads of New Orleans with engines whose motive power is derived from a supply of hotwater with which a large tank on the engines is charged from stationaryboilers. These experiments were attended with more or less success, sothat in the early part of 1876 the Crescent City Railroad Company of New Orleans gave an order to Mr. Theodore Scheffler, a mechanical engineerof Paterson, for eight engines of this kind to be built from his designs.The engraving represents one of them without its cab. The constructionis thus shown more clearly than it would be with the cab on the engine.

It has a cylindrical tank 31 in. in diameter and 9 ft. long for holdingthe hot water. The capacity of this tack is about 300 gallons. The driv-ing-wheels are 30 in, in diameter, and the leading wheels 20 in. with awheel-base of 5 ft. 7 in. The cylinders are 4^4 x 10 in. The valve-gearconsists of a main valve, which works full stroke at all times, and controlsthe exhaust, with a steam valve on top worked by a link, which governs theadmission. Both valves are, however, worked by the same link. Thisvalve-gear has been patented by Mr. Scheffler. The whole weight of theengine with the tank full of water is 8,700 lbs.

The tanks are charged with water from a stationary boiler which isheated up to a temperature due to a pressure of 220 lbs. per square inch.With such a charge the engines run about six miles with an ordinaryloaded street-car ; the pressure in the tank at the end of the run is thenreduced to about 40 lbs.

It is of course important to use the steam with the utmost economy, andas the pressure varies between such wide limits, the valve-gear referred towas employed in order to regulate the supply of steam required by the cut-off alone, and thus use the steam in the least wasteful way. The separatecut-off valve gives a much wider range of cut-off, and thus permits a muchmore perfect adjustment of the supply of steam than does the ordinary link-motion with a single valve.

The tank and the other parts of the machine are all protected as per-fectly as possible from radiation, and every possible device is employed touse the steam economically.

The stationary boilers used are of what is called the sectional or“tubulous” variety. They consist of sections of 68 2 in. inclined tubes, 7ft. long, which are attached to ordinary tube plates. On the outside ofeach of these plates is bolted a hemispherical cast-iron cap, which inclosesthe ends of all the tubes. Each cap is connected with a horizontal steamdrum placed above the tubes, 2 ft. in diameter by 11 ft. long. The water