17-06-2014, 04:20 PM
Hi Again
to answser your specific questions:
Q- But one question Signal 109 MAR not required as both routes have same speed. Could you please explain more? I think that by the nature of turnout we need to have delay time to proceed a train. Did I miss something?
A - The normal way of warning of a speed restriction (turnout, curvature, poor track quality, whatever) is by lineseide signage , driver instructions (The sectional appendix), and driver training, collectively known as "route knowledge". therefore a signal such as 104, which leads from a 100 kmh line, via 40 kmh turnout, to a 140 kmh line , needs neither a route indicator nor MAR approach release condition. The driver approaching this signal, even if it is green, or if did not exist at all, would know that the maximum safe speed is 40 kmh , and adjust speed accordingly.
Usually where there is a turnout and choice of route, there is a "faster" and "slower" option, such as 111. if the driver sees only yellow or green in this signal, they control the train speed within the higher speed profile (140kmh). the route indicator is used to inform the driver that a lower speed profile applies - in this case 40 kmh for the turnout. Because the speed differential is very great, approach release from red (MAR ) is also require to enforce this speed reduction.
Now, in the case of 109, the approaching driver knows that the highest speed profile available is 40 kmh through points 206, regardless of the final train destination. Therefore, MAR is not needed to force this reduction (just like 104 signal). Route indications are still required to confirm (in case of misrouting for example) the actual route, and since there is no "fastest" route, an indication would be used for both options.
Q Regarding the Route 115B, yes it is. I have one question. It has no possibility to have a train go to down branch from Signal 115 because of the point direction of switch diamond. It is not possible to have a route that 209A is normal and 209B is reverse. Am I right?
A - the switch diamond cannot allow any movement from 115 to 151 - it only allows "straight across" moves. My point is that, when the move from 151 to 153 passes on the Up Branch, the driver will be confused that there is a Down Direction Signal 151 to be ignored, but no signal to obey - this is the "parallel lines" rule. the confusion is removed by providing an extra down direction signal on the Up branch, alongside 151.
Hope this helps
best wishes
Reuben
to answser your specific questions:
Q- But one question Signal 109 MAR not required as both routes have same speed. Could you please explain more? I think that by the nature of turnout we need to have delay time to proceed a train. Did I miss something?
A - The normal way of warning of a speed restriction (turnout, curvature, poor track quality, whatever) is by lineseide signage , driver instructions (The sectional appendix), and driver training, collectively known as "route knowledge". therefore a signal such as 104, which leads from a 100 kmh line, via 40 kmh turnout, to a 140 kmh line , needs neither a route indicator nor MAR approach release condition. The driver approaching this signal, even if it is green, or if did not exist at all, would know that the maximum safe speed is 40 kmh , and adjust speed accordingly.
Usually where there is a turnout and choice of route, there is a "faster" and "slower" option, such as 111. if the driver sees only yellow or green in this signal, they control the train speed within the higher speed profile (140kmh). the route indicator is used to inform the driver that a lower speed profile applies - in this case 40 kmh for the turnout. Because the speed differential is very great, approach release from red (MAR ) is also require to enforce this speed reduction.
Now, in the case of 109, the approaching driver knows that the highest speed profile available is 40 kmh through points 206, regardless of the final train destination. Therefore, MAR is not needed to force this reduction (just like 104 signal). Route indications are still required to confirm (in case of misrouting for example) the actual route, and since there is no "fastest" route, an indication would be used for both options.
Q Regarding the Route 115B, yes it is. I have one question. It has no possibility to have a train go to down branch from Signal 115 because of the point direction of switch diamond. It is not possible to have a route that 209A is normal and 209B is reverse. Am I right?
A - the switch diamond cannot allow any movement from 115 to 151 - it only allows "straight across" moves. My point is that, when the move from 151 to 153 passes on the Up Branch, the driver will be confused that there is a Down Direction Signal 151 to be ignored, but no signal to obey - this is the "parallel lines" rule. the confusion is removed by providing an extra down direction signal on the Up branch, alongside 151.
Hope this helps
best wishes
Reuben