Tehachapi, BC

[Sokramiketes]

Well, if it was seriously an issue you could cut the strips in half and have each truck independently feed a bridge rectifier, the output of which would then feed the lighting circuit. Yeah, PITA, but solves the problem. Or forget Kato's lighting kits, pull the wheel wipers so even a single truck doesn't bridge the gap and use Rapido's Easy-Peasy setup. There are ways around it.

Of course, but why build a layout that certain stuff can't run on?   

[jagged ben]

Gary, I've actually been staring at your diagrams for a while now, and while I don't (yet?) have 'the perfect solution', there's some points to make...

First, to re-iterate...
X-Blocks, X-blocks, X-blocks!

An X-block is just a block of track that switches it's source of power according to how a turnout is thrown.  (It's easy to do this with a relay or two.)

For example, in Coxy's diagram...

...

...

...  it would be really easy to make Green part of the 'A' reversing block only when the crossover at 1 is closed, and yellow likewise part of it only when the crossover is thrown.  This would basically get you your 'Medium-block' or even your 'Long-block' solution but with no possibility of the 'trains on both mains' problem.

(No need for all those colored sections to all have expensive reversing units either!)

With that said, your track plan is complicated, particularly by that route from storage to Bakersfield.  It makes for numerous possible X-blocks, and wiring lots of them isn't necessarily worth the trouble.   Right now I don't see a strong case to argue against trying your 'short-block' solution (with the styrene filled gaps) and seeing how it goes.  If it doesn't go well, you can cross that bridge later, I think ... probably with X-blocks.

Second point...

Another option is for block A to be 7' long on Track 1 (and limit passenger trains to 7'), then make the entire Bakersfield yard a reversing section.  But that still has the problem that trains can't enter and leave the yard simultaneously on Tracks 1 and 2.

The problem you mention could be  handled by power-routing the staging yard tracks, with one end assigning the reversing block and the other end assigning the normal polarity.  You'd need some logic to prevent both ends from being aligned to the main track, but that's probably feasible, most easily if turnout control goes through JMRI. 

Also, FWIW, we have a block at the club that is both a siding and a staging yard in a similar reversing block.  It seems like it just never happens that two trains enter both ends of the block at the same time, even though we stage meets there often enough.   Your mileage may vary...

Again, possibly a solution to a non-existent problem, but maybe something to remember if the problem actually crops up...

[GaryHinshaw]

Great feedback guys!  You have certainly forced me to think deeper about this problem.  As much as I like the simplicity of the short-block solution - only two 3' sections of A/R, done - I can't quite get past the passenger train problem (or the 10-unit light engine move) that this scheme precludes.

Offline, Professor Dance has convinced me to consider a more brute-force approach, wherein the balloon tracks in the yard each have their own A/R.  At some cost (in $) this would satisfy all my desires for operational flexibility in the yard and make blocks that are longer than the longest train.  If I go this route, the remaining problem is isolated to how I handles the reversing section at C:



In actual practice C is a standard-length crossover between two parallel but opposite polarity main lines.  Is there a way to handle this situation with X blocks?  The catch with a full-length A/R section here is that the south staging helix yard is only ~4' from C, so a long block has to either penetrate the yard, with multiple boundaries at the north end, or penetrate the NB main heading into Bakersfield.  If there is a clever way to avoid that, I'm all ears.

Thanks again!

[Sokramiketes]

Offline, Professor Dance has convinced me to consider a more brute-force approach, wherein the balloon tracks in the yard each have their own A/R.  At some cost (in $) this would satisfy all my desires for operational flexibility in the yard and make blocks that are longer than the longest train.  If I go this route, the remaining problem is isolated to how I handles the reversing section at C:


Thanks again!

This makes sense.  How will you be selecting inbound and outbound turnouts on the balloon tracks?

If you set up a rotary knob to select each track, the power can route through the knob.  So the common line into the knob can be driven by the output of the reverse loop controller.

Add one rotary knob on the inbound side, and one rotary on the outbound side, and you just need two reverse loop controllers.

Power is then off for any track that's not aligned inbound or outbound, minimizing runaways/sound decoder power draw, etc.

[eric220]

Gary, on the left, what about starting the reversing section near where you have "N ->" and running clockwise around to short of the yard near the "S", mirroring what's on the right?  Obviously since this is a schematic, I have no idea how much track is actually there, but it seems the simplest place to put it.

[jagged ben]

In actual practice C is a standard-length crossover between two parallel but opposite polarity main lines.  Is there a way to handle this situation with X blocks?

YES!  Each of those three tracks would be part of the reversing block if the turnouts are lined for it, or 'normal polarity' if they are not.  That way north bound and southbound trains can leave from that section at the same time.

It's a little complicated because there are three (two would be much simpler), but you just draw the second two partially from the first.   If you need help with the relay logic I can spell it out for you... later.  Right now I gotta eat.

[GaryHinshaw]

Skibbe, I think Mark was actually suggesting something along the same power-routing lines as you for the yard.  That section is entirely virtual still, but it is clearly a solvable problem and I'll bone up on power routing options before I move ahead with it.  In the meantime, I think it is safe to assume that reversing for that section will be contained within yard limits.

Eric, my schematic is highly schematic: the loop at the far left is the entire visible main, about 5 scale miles, so I'm not too keen to go that route.  Worth suggesting though.

For the connector at C, the physical track arrangement is more like this:



In practice, this is wrapped around the lowest 3 levels of the Vortex™, but I have unwrapped it for this schematic.  Suffice it to say, the black and red sections have opposite polarity if no other precautions are taken, and they would meet at the crossover C.  On the left, the red arrows connect to the black ones after traversing the full layout.  On the right, all tracks head to yards.

One possibility for a reversing block is shown in blue here:



To make the block long enough, without making an incursion to the Bakersfield-Edison main, I need to penetrate the Mojave staging yard.  I could designate (only) one of those tracks to host the reverser, avoiding issues with trains at both ends of a reverse block in the other yard tracks; further, I could interlock the yard lead so that, if the crossover C is set to cross, the yard lead is set to the blue track.  That way trains taking the crossover are forced to stay in a long reverse block.  Trains traversing other routes entirely on the red side of the schematic (common) can traverse a short reverse section without causing shorts (right?).

Thanks,
Gary

P.S. I'm still curious about this question, even though I don't think it applies any more:

At the time, it raised a question that I never found the answer to: what happens when you have two adjoining independent reversing sections?  If they start off with the opposite polarity, why don't the two reversers duke it out in an infinite loop of simultaneous polarity switching?  This may be an unlikely scenario, but not a forbidden one, as far as I can tell.   

[jagged ben]

One possibility for a reversing block is shown in blue here:



To make the block long enough, without making an incursion to the Bakersfield-Edison main, I need to penetrate the Mojave staging yard.  I could designate (only) one of those tracks to host the reverser, avoiding issues with trains at both ends of a reverse block in the other yard tracks; ...

Or you could use the X-block solution I explained in my last post.

P.S. I'm still curious about this question, even though I don't think it applies any more:

Me too.   I'm also curious, with respect to your Bakersfield staging yard, what happens if you power the same track with two reversers.  That is, if you power route both ends of the yard, each with it's own reverser, do you have a problem if they both align to the same track?

[GaryHinshaw]

I think I'm catching up with you now jb.  You are saying I make all 3 yards tracks potentially reversible.  The function of the X-block is to make sure the selected route is reversible but the other two are fixed polarity.  (And if the crossover is lined straight, they can all be fixed.)  Suppose I have trains parked in 2 tracks and I line the lead for one of them.  Does the switch from fixed to reversible when a block is occupied have any side effects?  That seems like it should be ok, but I think I need to make sure the north end of the block is not bridged by a train.

I'd love to see some circuit specifics if you have time.

[jagged ben]

Does the switch from fixed to reversible when a block is occupied have any side effects?  That seems like it should be ok, but I think I need to make sure the north end of the block is not bridged by a train.

The only potential side effect is a very momentary loss of power, but I've never seen a relay that was too slow in this respect.

Bridging the north end of the block is not a problem.  If a train is leaving one of those tracks northbound, then the polarity is already aligned, either by the reverser or by the X-block relay.  Switching from one power source to the other doesn't change the polarity under either end of the train and shouldn't affect it.   

The only thing you really need to do is to setup signals so that if a train is leaving one end of the block and another train is following it, the second train doesn't pass into the reversing block until either a) the first train is all the way out of the block, or b) the turnouts into Mojave staging are lined for a different track.  But from an operational point of view, adding 5' of following distance is the most reasonable and prototypical sort of restriction to live with.  Trains ought to be following at a safe distance and not entering occupied blocks in any case.   


I'll try to draw up the relay circuit for you when I have a few moments.

[C855B]

... Trains ought to be following at a safe distance and not entering occupied blocks in any case. ...

Wellllllll... tell UP that. The way CTC works these days is if there is a train following and cleared for movement, the signal goes to "restricted" and not absolute, even with the controlled block still occupied. This gives a stopped train (from a crossover or siding, for instance) the opportunity to start moving, and saves the several minutes it would otherwise take for the same signal to indicate "approach". Frequently the aspect improves before the following train hits the control point, but it acknowledges that there is little harm in having a slower following train in the same block, as long as the engineer knows he is to follow the rules regarding restricted aspect(s).

Same sort of thing as a "G" placard in double-track ABS - a red signal doesn't necessarily mean "stop".

[GaryHinshaw]

Time for another incremental update with further progress on the Vortex:



I know, there is way too much happening in this shot to even comprehend it.     Here is a brief tour:

* Far left - main line into Bakersfield (north staging).  See also below.

* Far right, against the wall - the throat of the stub-end storage yard which has 9 14' tracks off to the right.

* Centre - the "race track".  The outer two tracks are the Bakersfield to Edison main line which loops through the Vortex once to gain elevation so that Edison can sit above the storage yard with adequate clearance. 

The inner track is part of the connector from the storage yard to the south staging yard, which will reside in the helix still to come above the race track.   The first 2+ levels of the connector are single track (labelled 1,2,3).  At the point marked 3, the line splits into 3 sequential tracks for managing south-end traffic going to and coming from the hill.  I plan to install a view block between the mainline and connector track in the race track.

* CP Charlie - this is Control point Charlie, a crossover that connects the east and west (or north and south) ends of the line for continuous running.  A train coming down the helix out of Mojave can sneak across and be northbound again for a quick sprint to Bakersfield, where it can reverse in the balloon and head back out.

* Not shown is a straight connector across the back that joins the storage yard to Bakersfield.

Here is the view just to the left of the Vortex:



This is the terminal manager's pit, where all of the staging moves will be run from.  The track on the left is basically the yard limits for Bakersfield.  CP Charlie (just off to the right) and the staging helix are both readily accessible from this spot and the storage yard is not too far away.  Hopefully this proves to be a manageable job...  especially since it will usually be me doing it.

One by-product of getting this lower level bench work in is that I also made a permanent home for my CD's.  I had to cut down two shelves off my existing rack, but I built a second one to make up for it.  Both are now comfortably tucked away and add a little colour to the area.

Now for a bit of a dilemma: as I build up the levels of the Vortex, it is clear that I should lay and test the mainline track in the race track before building up the levels above.  My plan is to use ME concrete tie track for that section (and Peco for all of the pure staging).  However, ME track is currently out of production, and I only have enough on hand to finish the more visible sections of the first deck (Edison to Bealville).  If I go ahead and use the ME track here, I am gambling that it will be back in production before I'm ready to lay the rest of the first deck... but no other option is palatable to me.  The N scale supply chain can be maddening.

Thanks for looking.

[Seligman Sub]

The n scale supply chain can be maddening.

Understatement of the year!  Looking good, keep 'em coming!

[John]

WOW ,.. it makes my head hurt just tracing this vortex

[Scottl]

I'm always amazed at the clean and finely crafted look of your benchwork.  This is an amazingly complex bit of of construction.

Have you contacted ME to see what they plan in terms of the concrete tie track?  They make it in the US, I believe, so perhaps they can give you some advice about future availability without the added challenges Atlas faces with Chinese production.  Just a thought.