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Old Posted Jan 17, 2018, 7:35 PM
Liberty Wellsian Liberty Wellsian is offline
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Join Date: Oct 2015
Posts: 810
Quote:
Originally Posted by Hatman View Post
I agree that the 10 minute layovers have a purpose as far as mitigating delays, but I disagree that they need to be 10 minutes long. Here, I made everyone a neat chart to look at:



What I've done is I've found the layover times for each endpoint by looking at these schedules (Blue Red Green Silver) and then I took the layover time and divided it by the time it took the train to reach the layover location. Basically, since it takes 51 minutes for a Blue Line train to get from SLC to Draper, and the layover time is 6 minutes, the layover is 12% of the trip time.

This percentage is what is really important. A Blue Line train can be 12 percent late arriving in Draper and still be able to leave northbound on time. A Red Line train can be only 10 percent late arriving at University Medical and still be able to leave on time. But the S-Line? It can be 100 percent late, or take twice the time it usually takes to get to either end of the line, and still be able to depart on time.

What I'm suggesting is that since the S-Line is only 2 miles long, it should have the shortest layover times compared to the other TRAX lines. Instead it has the the longest of any line. What kind of delays will the streetcars accrue in 2 miles? 2 minutes? 3 minutes? Not nearly enough to cause 100% delays, and not enough to justify a 10 minute layover. Let's hold the S Line to the same standard as the Red Line at Daybreak, and let it have a 22% layover. That would give the S-Line 2.5 minutes of laying over. Then lets be generous and give them another 2.5 minutes, just in case. We now are at a 44% layover, or 5 minutes. That means we could run the S Line every 15 minutes right now and not need to wait until 2020 to do it.
I'm of the opinion that 15 min frequency still won't be enough anyway. The line is so short and the train so slow that it probably needs a higher frequency. As close to on demand as we could reasonably get it, which means the whole line needs to be double tracked.
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