What happens if 2 locos go over different reverse loop gaps at the same time, you will have a short? Isn't this why reverse loop gaps are cut at a turnout, so theres no way of 2 locos entering same time?
WardR What happens if 2 locos go over different reverse loop gaps at the same time, you will have a short? Isn't this why reverse loop gaps are cut at a turnout, so theres no way of 2 locos entering same time?
Sometimes, it is poor planning. Sometimes it is unavoidable. Two locos will enter or exit or simultaneously enter and exit the reversing section. Or, a single train will both enter and exit the reversing section at the same time. The result is a short.
Rich
Alton Junction
The thing is, most reverse loop examples show the most trivial kind - the diverging leg of the turnout loops back to the straigh tleg of the same turnout. Ineed on such a simple arrangement it would be impossible for one train to enter at the same time another was leaving - or even impossible for having a train longer than the loop, unless you really like to smach your trains up.
Most people wuickly recognize such arrangements as reverse loops. But in the realities of a more complex layout design, you can sneak in a reverse loop and not initially realize it. A more complex track arranagment that just so happens to have one path where the direction of the train can reverse back on the same section of track it came from is a reverse loop evne if most of the time the trains take an alternative route, and needs to be planned for. Those can actually be some of the hardest ones to configure, becuase technically the 'reversing section' may be very small - but then you have the clear possibility of longer locos and cars with metsl wheels crossing the gaps on both ends at the same time.
Wyes are the same way. Yes, include one of the turnouts and theoretically there's no way two locos could occupy the same track, crossing both ends of the isolated section at the same time, unless they were on a collision course. But - what if instead of a simple single track around one leg this was actually a larger section of the layout, with maybe even a passing siding in the middle? Then you could easily have a train entering from both ends at the same time, in a completely legitimate operation.
That's why such tricks as drawing the plan with both rails and coloring each one differently without lifting the pen are useful. If the red rail runs into the black rail - you have a reverse loop somewhere. The tricial designs pretty much sort themselves out. The more complex ones - that's where you need to plan it both from an electric perspective AND an operation one.
--Randy
Modeling the Reading Railroad in the 1950's
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