I’ve a couple of questions concerning reverse loops and staging on reverse loops using DCC. My staging yard is a 4 track loop. The staging is to be operated in one direction. Each loop track is long enough to hold two trains. I’m thinking sort of like a 4 track arrival and 4 track departure yard. If a train was to run through any loop it would be only one at a time. Question #1: Can I use a single reverser module to power the in-bound ladder and tracks? Question #2: Do the reverser modules burn (arc) the wheel sets when they cross the gap? Question #2A If so what is your experience? Question #2B Would the an optical detector running an relay be better. (As in DC days)? Michael
Question 1: The rule for a reverser is that you cannot cross two ends at the same time. Firstly work out your longest consist - all cars with electrical pickups: engines, passenger cars, some cabooses. Any reversing section shorter than your longest consist = short circuits, won't work. Secondly you can power two reversing sections with one auto reverse module, but only if one train can only enter or exit one end of one section at any one time. If you put the whole of both ladders into the reverser module, as shown in my badly drawn attachment, then you've just got one track to/from the "rest of the world", at which point you've got no problems from multiple trains. Question 2: no idea. Theoretically it'd be(/become) a problem. You can get reversers with a "portal" in front of the actual polarity-changing section. The idea being the portal detects the incoming train and switches the main body before a short occurs. May be a bit more pricy than a simple "4-wire" reverser. .. Can't find what I want on google, so no links, sorry. Badly drawn reversing loop with sidings, gaps where shown, main line on right and reverser on left.
I think that anything with metal wheels has to be counted, not just cars with pickups. The auto reverser operates when a short occurs across two sections which are out-of-phase, and a metal wheel bridging the gap will provide this. (Might even be the primary agent.) I saw an article a year or two back about the arcing business. They tested a number of makes and they varied from quite badly to hardly visible. Hovever, given how often most locos will go through this (compared to general wear and tear and cleaning) I doubt it is a big problem. It should also only be the leading wheel of the leading loco, so if you are paranoid you could always rotate the wheelsets on the locos periodically, like people sometimes do with car tyres
Thanks for the replies. One gap would be before the upper ladder in your drawing, four more gap will be at the far end of the loops away from the ladder. One half of any loop should be longer than my longest train, due to the lenght of sidings and yard tracks. (this is yet to be measured on the layout) Michael S
I prefer to wire one reverse loop to a reverse loop module. If you wire two reverse loops to one reverse loop module/switch, it's inevitable that there will be a time when two trains will enter the reverse loops that are wired to one module. It's safer to purchase a reverse loop module/switch for each reverse loop. Stay cool and run steam.....
Is there some reason for doing it this way that you're not mentioning? Otherwise I can't see the advantage compared to the way ATSF admirer drew it. In fact I can see a big disadvantage to your way, which is that instead of just watching at the turnouts (which you have to do anyway), you'd have to watch where your trains are in the middle of the yard, even if you weren't putting two trains on a track. If you left any loco consist on top of the gaps while you brought in another train you'd bogart the whole yard's power. Or to put it another way, if you do it like in the drawing, your only worry is not crashing trains into each other, whereas if you do it your way, you additionally have to watch the gaps. Anyway, the answer to question #1 is yes.
There are several things to take into account.(I'm figuring this out as I go) First I'm cheap, I'd rather buy another locomotive than another reverse module. This staging yard is hidden from the operating part of the as to be completed mushroom style layout. I'm using a recycled computer as part of my dcc system. (running JMRI software)The yard throat is on a usb camera so the loco or caboose of a given train can be seen and stopped well clear of the far end of loop gaps. the camera also shows the trackside turnout signals indicating how the turnout is thown. (I don't yet have feedback with dcc) see http://www.trainboard.com/railimages...00/ppuser/6862 for my track plan and photos of this area. Thax Michael S
So long as you don't anticipate one train arriving into staging on one track, and another simultaneously departing staging from the same or another track, then gapping the two tracks just beyond the first turnout (and having all four staging tracks as a single reversing section) as shown in ATSF's diagram will work just fine. If you can't guarantee against the above arrival/departure scenario, I would place the gaps beyond each turnout, making each staging track a separate reversing section fed from individual reversers. All turnouts (not just the first) would then be part of the mainline power district. Operationally, I would prefer the latter, as it provides more flexability.
Making each track it own reverse section was my first idea, but I'd like to simplfy/mimimize the hardware.The main line into the staging is double track so the ladders are one arrival and one departure. The proposed reverse section(s) would be the in-bound ladder to the far end of the loops. (about 8' this is an N scale layout). One train in at a time as well as one train out at a time.(once the outbound train had moved to the departure side of the loop) Michael S
(my bolds in the quote) I think you have a big risk here. With the setup you seem to be describing you could easily (even if not intentionally) have a train entering and another leaving at the same time. Pop :sad:
Always an objective, of course, but consider that a PM42 will handle all four tracks independently, at less cost then 4 separate autoreversers.
I checked out the PM42, as the indepenent loop tracks do seem the best idea, as expressed in the various replies. (thank you all) The pm42 must be programed on a digitrax system, at he moment I'm using an atlas/ lenz compact plus xpa to handheld throttles (phones) and to the computer via a modem. Are there other resonablly priced reverse modules? $20 per loop seems ok $40 per loop seems steep at this point.
You don't need a complete Digitrax DCC system, only a Digitrax throttle. An old DT100 (which you can probably find used at the usual places) should do fine. An alternative would be individual AR1 units (no throttle required) at less than $25 each, or, with a little operating discipline, you could get away with a single reverser for now, and add others as the budget allows.
Thank You for your replies. This is what I took away from this discussion, correct me if I am wrong; 1 Wheel arcing is not a big issue, with the state of the art reverse modules. 2 One reverse module, per reverse section, is the most flexible choice. 3 One reverse module will serve several tracks, if only one train crosses in or out of any of the sections at a time. (expect operatior caused problems) Thanks Michael S
I have placed the gaps between the arrival side and the departure side at the far end of the loops. (more than a train length) Also note there are different ladder tracks lending in from and out to the double track main. There appears to be no electricial problem, so as, this is not an ideal, but a stop gap. The probelms will be operationial. I can start with one reverse module and add others as need the need or flexiblity require. Michael S
