606 repokt — 1884. 



only one movable point rail, the other being fixed like a frog point ; bn t 

 this is not a good arrangement. If the movable point rail is placed inside 

 the curve diverging from the main line, then, when it is set right for the 

 diverging line, it acts not as an ordinary point rail, but as a guard rail, 

 for which it is not suitable; also, no matter which way the switch is 

 placed, the support to the treads of the wheels is not as much as two 

 point rails give, and the stock rail alongside the fixed point wears out the 

 same as a wing rail in a frog wears out at the frog point. One of the 

 greatest dangers with the split switch — that of loose wheels working in 

 to catch the end of the open point — is doubled in the single point switch, 

 for a loose wheel will catch as easily on the end of a fixed point as on an 

 open point, and when the point in such switches is open, there are two 

 places where there is a liability of trouble. In this connection it would 

 be well to say that split switches should always be made trailing if possible ; 

 never facing the travel if it can be avoided. On single track lines, with 

 travel in both directions, it is not feasible to carrj^ out this precaution ; 

 but on double track lines the matter should never be overlooked, as it may 

 prevent serious accidents. If a trailing switch be operated by a spring 

 or weight, so that, in case the switch is wrong for an approaching train, 

 the flanges of the wheels advancing from the fixed rail on to the movable 

 point rail can overcome the resistance and move the points into their 

 proper position, thus avoiding a derailing of train, then the switch 

 becomes a self-acting ' safety switch.' 



Mr. William Lorenz, who has for a long time been chief engineer of 

 the Philadelphia and Reading Railroad, designed a simple and practicable 

 form of self-acting split switch, with a spring securely holding the points 

 against the stock rail, so that the switch was safe for all trains approaching, 

 facing the switch, at the same time that it was self-acting as a trailing 

 switch. His switch being the type of all of these, his name is deservedly 

 attached to them, and they are known as the ' Lorenz Safety Switch.' 

 Fig. 2, Plate VIII., shows the Pennsylvania Steel Company's improved 

 pattern of this switch. The general arrangement is the same as already 

 described, except as it regards the spring, which is steel, double coiled, 

 and is generally arranged in a yoke on the side of the front connecting 

 bar, where it can be conveniently reached for adjustment. The length 

 of the points is 15 feet, and the throw is 3i inches, the switch stand 

 throwing 4 inches to give proper compression to the spring. In the 

 original Lorenz pattern the points were usually made much longer, even 

 up to 30 feet. 



A shorter pattern of safety switch is made for yard service, the point 

 rails being as short as seven feet six inches, with a flange way at the heel 

 of only two inches. 



The Pennsylvania Steel Company also make an automatic switch 

 stand, which, by the combined operation of a weighted lever and gearing, 

 holds the switch with a solid rigid throw, and renders it absolutely safe 

 for all ' facing ' trains, at the same time giving a signal indicating the 

 position of the point. It also acts automatically as a safety switch for 

 trains trailing over it from either track. When acting in the latter way, 

 the first pair of wheels over the switch set it right, so that the remaining 

 wheels do not have to open the switch each for themselves, as in the safety 

 switch with springs. 



In Wharton's Patent Switch, the great principle is always to pre- 

 serve an unbroken line in the main tracks, under all circumstances, and 



