I am working on a computerized dispatching system, using simulated two position CTC switch plates and I have a question.
All switches (turnouts) *except* 3-way have two states: normal and reverse. 3-way switches have three states. How is this handled with two position CTC switch plates?
\/ Robert Heller ||InterNet: snipped-for-privacy@cs.umass.edu
Robert,
There would be 2 switch motors, thus there would be 2 switch controls(your
3-way is just 2 very compressed turnouts).Jim Bernier
Robert Heller wrote:
JB> Robert, JB> JB> There would be 2 switch motors, thus there would be 2 switch controls(your JB> 3-way is just 2 very compressed turnouts).
Which means that a 3-way switch actually has 4 states, one of which is an 'impossible' state. I've set up a test case where the 4th (impossible) state is disallowed by the CTC logic -- only one switch plate can be set to 'reverse' at a time.
Is this logic correct?
JB> JB> Jim Bernier JB> JB> JB> Robert Heller wrote: JB> JB> > I am working on a computerized dispatching system, using simulated two JB> > position CTC switch plates and I have a question. JB> >
JB> > All switches (turnouts) *except* 3-way have two states: normal and JB> > reverse. 3-way switches have three states. How is this handled with two JB> > position CTC switch plates? JB> >
JB> > \/ JB> > Robert Heller ||InterNet: snipped-for-privacy@cs.umass.edu JB> >
JB> >
JB> JB>
\/ Robert Heller ||InterNet: snipped-for-privacy@cs.umass.edu
Yes, this logic is essential for a true 3-way switch where the two sets of blades are superimposed, for the more common 'tandem' switches where the two sets of blades are one behind the other it is still usual to apply this same logic if the switches are within an interlocking. Which they are, of course if you are using a CTC machine. Note that if you are not concerned to use prototypical CTC machine levers then the simplest way to achieve this interlocking is to use a three position lever. Keith Make friends in the hobby. Visit Garratt photos for the big steam lovers.
With the exception of the stub type turnout, there really isn't any three way turnouts. The two turnouts of the "3 way" turnout are really just two turnouts that are very close together and overlapped to each other. As such, one of them follows the other and the diagram should show the two turnouts as such without the overlapping. Do make sure that the two turnouts are interlocked together in the same block or you may end up with a train trying to hold over in one part of the turnout and fouling the rest of the trackage.
-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works every time it is tried!
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