. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . wide by 1^2 in. long, and communicate with the mainsteam passages between the valve and cylinder. A diagrammatic view of this starting arrangement isshown in Fig. No. 3, which indicates two positions ofboth the right and left cylinders. In the bottom viewsthe right piston is beginning its backward stroke and isexposed to full steam pressure, but as its crank angle iszero it cannot transmit any turning effort. The left pis-ton lias reached cut-off position of the main port; im-possible t
. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . wide by 1^2 in. long, and communicate with the mainsteam passages between the valve and cylinder. A diagrammatic view of this starting arrangement isshown in Fig. No. 3, which indicates two positions ofboth the right and left cylinders. In the bottom viewsthe right piston is beginning its backward stroke and isexposed to full steam pressure, but as its crank angle iszero it cannot transmit any turning effort. The left pis-ton lias reached cut-off position of the main port; im-possible to start the locomotive without taking slack. With the starting ports, steam can enter the left cylin-der through the small slot indicated and exert pressureon the piston until it reaches the position shown in theupper figure of the diagram. At this point the smallport is cut off by the valve. It will be noted that theright crank has now reached a favorable angle which will. LElFT RIGHT Fig. 3—Diagrams Illustrating the Functions of the Starting Ports permit starting the locomotive without taking slack. Thecut-off position of the auxiliary port is from 80 per centto 85 per cent of the stroke. This starting means is ex-tremely simple, efficient and entirely automatic. While those who have given the subject sufficient studyrealize the necessity for providing some starting meansin a limited cut-off locomotive, there are others who claimthat such means are not necessary to successfully starta locomotive having the cut-off limited to 70 per cent ofthe stroke. That such reasoning is fallacious will beproven by the following Fig. No. 4. In this illustrationthe white circles represent the positions of the cranks ofa locomotive having full gear cut-off at the instant thatthe valve has just closed the steam port governing thefollowing crank. This is the position in which the loco-motive will have the minimum starting effort. If we takeas an example a locomotive ha
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectrailroa, bookyear1901
