Separate Power for Yards vs. Main Lines?

[Gluefinger]

I'm in the process of building a layout in which the main line passes througha small yard- a rough "drawing" of it is below. (Equal signs are the main line, slashes are switches, and dashed lines are the yard tracks)

My question is- can I wire the layout so that the main line is independent of the yard tracks- one power pack for the main, and one power pack for the yard? I'm sure this is possible, but I'm not sure how to wire it so that engines can come off the main, drop cars off, and pull back out (or vice versa).

I'm running straight DC- no fancy tricks here....

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[MisterBeasley]

Yes, you can do this. It's pretty much the same as wiring two blocks with independent DC cabs. Of course, when the engines are in the transition area you need to carefully match both direction and speed.

[bogp40]

QUOTE: Originally posted by MisterBeasley

Yes, you can do this. It's pretty much the same as wiring two blocks with independent DC cabs. Of course, when the engines are in the transition area you need to carefully match both direction and speed.

I agree with MisterBeasley. Consider the use and all possibilities of how you want to operate the yard to figure where your transition "block" or "blocks" will be. On a double ended yard the tranition could be the entire mainline track extending beyond both yard turnouts. This section can be controlled by the Yard cab/ power pack w/ a double pole, double throw-center off switch. The sw is marked by direction entering from mainline for aligning polarity to enter the yard. The center off will allow normal use of the main from mainline cab/ powerpack. You may also want to include a yard lead as part of the mainline cab to allow smooth tranition from mainline into yard. then you can throttle up the yard power after turning off the mainline block.
There are many options to accompli***his. Others on this group can help once you know exactly what operation suits you best.
Ever consider going to DCC? It's reasons like this that makes DCC so great to have.
Bob K.

[rrinker]

Definitely wire at least the transition to a toggle. The arrival/departure track(s) for sure, that way your road train can pull into the yard, and then you can switch to the yard cab for the switcher to classify the train.

--Randy

[dehusman]

Why wouldn't you want to wire it for conventional two block DC? It does exactly what you want without the need for worrying about a transition It might cost you a couple extra switches.

Dave H.

[Gluefinger]

I'd like to be able to operate, or at least park a switcher in the yard while a train is on the main- I would love to switch to DCC, but I'm on a student's budget, and I'm moving out in two years, so I'm worried that if I purchase a DCC system now, by the time I'm done with college, it will be obsolete (and unused for 4 years).

[tstage]

Chris,

First of all, a few questions:

1. How many locomotives do you have? How old are they?

2. Do you already have two power packs needed for two-block cab control? Or, will you have to go out and purchase one or both?

3. How much will you need to spend on wiring, switches, toggles, etc. to achieve two-block cab control?

4. How much money to you have to spend on MRRing?

You can pick up a Bachmann EZ Command DCC system for as little as $53. I picked mine up from Wholesaletrains.com. (Hmmm. I just checked Wholesaletrains.com. It looks like the Bachmann EZC has gone up to $59.00. BUT...that's STILL cheaper than the regular $100 MSRP.) Decoders can be had as cheap as $15. And you can run one non-DCC locomotive using the Bachmann EZC. However, it's best not to run it for a long period of time that way.

This is just my opinion. If you are going to have to fork out some dough for either point 2 or 3 to achieve two-cab control, then I woud just go ahead and dive right into DCC. However, you would be the best judge of that, knowing your limited resources.

Tom

[Adelie]

When I last wired a layout for DC, I did pretty much what Chris is proposing. That gave me an easy way to control yards and spurs at slow speeds while running main line operations at main line speeds.

For whatever it is worth, the primary yard on the current layout project will be a separate power district in DCC when it gets built. I'm essentially treating it as a layout within a layout.

All that said, if you are going to buy two new power packs to accompli***he split districts, I'd strongly consider DCC at some level.

[Gluefinger]

Thanks for all the help and suggestions everyone- for your questions, Tom...

1. I have about 20 locos....about half from pre-DCC days (mostly Athearn blue box, and a few early 1990s Atlas locos), and then the other half are more recent models. I'm not so worried about installing DCC as to cost...I'll be getting a job soon though, so I might be allright. Only problem is, I want to build the layout as a summer project and have it done in a couple of months.

2. I have two power packs- one isn't very powerful, but that's allright since I won't need much juice for the yard.

3. There's enough wire and other electrical paraphernalia (always wanted to use that word) from the old layout, so that probably won't be a problem either.

4. As of now, I have about $100 saved up- but I hope to get a job by the end of summer (Schedule is a little tight right now- I have to wait a bit).

This whole layout is a summer project that my friends (who are non railroaders) and I are building- sort of a surprise. I hope to get it done by the end of summer, and unveil it to the public (hah) as soon as its done.

I suppose that it wouldn't be too difficult to change a layout over to DCC after it's completed? Especially a small one? This would be what I want to do as soon as I get a bit more income- the existing wires and power packs won't be really wasted after I pull them out, as they've been sitting around for years anyway.

[tstage]

Chris,

That does make a difference. Since you already have most of the stuff needed to run DC, that's probably the way to go.

I run a 4 x 8' layout, on DCC, only using two (2) wires. (Not the ideal, but it does work.) Once I nail down the layout design, I'll start running power busses and track feeders. The Bachmann EZ Command system only has 1 amp of power so I am limited to running a maximum of 2, maybe 3 locomotives simultaneously. (On a 4 x 8', 3 gets confusing enough.) I have newer locomotives so they don't draw much current.

If you are using this current layout as a learning experience, then I'd probably stick with the DC. Keep us abreast of your progess. Pics would be nice, too. [:)]

Tom

BTW, I've heard that if you switch your layout from DC to DCC, you can keep much of the already existing wiring to run your layout on DCC.

[MisterBeasley]

You can still use those DC power packs to run switch machines, turntables and lighting.

[dinwitty]

I do not believe in 4 years DCC would be obselete, NMRA has established it a standard,
in 4 years I want my DCC locomotive to run as well as now.
Not the same as computers.

[dinwitty]

Power routing turnouts need no switches....

more than one loco on the layout, may as well have track portions turn off,
best bet is route control for each track blocked up for best flexibility.
I wouldnt use 1 powerpak for main another for yard separate powers, route them all.

[wccobb]

Gluefinger: YES. You can do it with one switch. You need a DPDT (double pole, double throw) switch, such as Radio Shack #275-1633 (list $3.49). I recommend this - or any other screw terminal switch - much easier to change for correct polarity.
STEP 1: Use insulated rail joiners EVERYPLACE between the mainline track and the yard tracks.
STEP 2: Assuming you have both throttle & direction control in both power packs, connect the mainline throttle to the mainline as if there were no yard track.
STEP 3: Connect the center terminals of the DPDT switch to the yard tracks.
STEP 4: Connect the terminals at one end of the DPDT switch to the mainline power pack and the terminals at the other end of the DPDT switch to the yard power pack.
STEP 5: Troubleshoot. Set the DPDT switch so that the yard tracks are being powered by the mainline throttle. A locomotive on the mainline should now be able to run smoothly into, thru & out of the yard. IF it stops over the insulated rail joiners, turn power off, pu***he locomotive well into the yard & turn the power back on. It'll probably run backwards. Reverse the two mainline power pack wires at the DPDT switch and it should run correctly.
IN THIS ARRANGEMENT ( used to be called "Dispatcher Control") the mainline engineer takes his train out of the yard and goes on his way. The DPDT switch then is thrown to "assign" the yard trackage to the yard engine, which can now go about it's business on the yard throttle.
UNLIKE DCC, the mainline power pack will power anything in the yard when the yard trackage is assigned to the mainline power pack. You need one more block - a single insulated rail joiner in the track where you want to "store" the yard engine while the mainline engine is using the yard and a SPST switch to "kill" power to the yard engine when it's on that track.
That $3.49 switch is a lot cheaper than any DCC and all you need for this summer. And you've done nothing that will have to be ripped out should you wi***o someday go to DCC. (After 47 years in HO, I still run one locomotive or one lash-up of locomotives - at one time !!!!! )

[Gluefinger]

Thanks a bunch wccobb, just a couple things to clarify- on Step 1, does this mean two insulated joiners, or just one? Also, this setup allows me to use the yard throttle and switcher to enter the main as well, no?

I should start benchwork construction on Monday- look for a new thread then!

[Anonymous]

I've collected HO scale locomotives in New York Central for a long time.We now have a house with a basement that is all mine.The kids are gone,and around the walls 24 inch wide bench work and skyboard is being built..The money issure with DCC control is I still like engines.NYC lighting stripe models are introduced in limited runs.Steam engines you must buy when availible or you miss out.I have wire,good quality power packs;and have been buying cork roadbed ,and flex track and #6 turnouts for awhile.I 'm planning to have a large steam& diesel terminal good size yard and want the buildings that will make it a great looking layout.Being on a retirement income makes DCC impossible for me.I also enjoy my 1979 Corvette;and rifle collection so I see lots of DPDT swt's and lots of wiring in my future.We have had many great layouts in the past that were not DCC.I hope there will be one here in Central NY this year.GOOD LUCK CHRIS.

[wccobb]

Gluefinger: Step 1 "everyplace" means everyplace. I count five places in your rough drawing where a train can "cross" from the mainline into the yard. That equals ten insulated rail joints.
With the DC power system, the power pack connected to the track will run anything on that track. (I've an old powerpack that will run eight Athearn "bluebox" locos, ala CGW !!! ) With this arrangement you can run the switcher on the mainline, powered by the mainline power pack. And that will get the job done. But, if the mainline locomotive is out there, it'll run it too. You can run the switcher on the mainline with the yard power pack if you put in a second DPDT switch. Run the wires from the mainline tracks to the center terminals of the DPDT switch - as with the other DPDT switch, and connect the two power packs to the two DPDT switches (the mainline power pack DOES NOT go directly to the mainline tracks. It's gotta go to the mainline DPDT switch). Hope this helps.

[dinwitty]

I can see a number of buggywhos cropping up from this discussion.
There are other electrical issues to think about, you can have the main totally isolated from the yard tracks with 2 different powerpaks. The next issue is completed power going to the locomotive.
There are locomotives out there where one set of wheels pick up on one truck and the other set on another truck, but is common for steam loco models to pick up one side on the engine and the other side from the tender.
When you cross the gap between main/yard, your engine will stall.
Multi-powerpak layouts need common ground wiring.
You can take ONE wire and hook it between either terminal of the other powerpak as a Common ground wiring which should avoid stalling, but you should buy yourself a wiring handbook.
Getting in this hobby needs good basic wiring skillz.
And you have to think the rails as being exposed wires with the locos riding along picking up power from them.

[Gluefinger]

But this only happens with the above-mentioned engines, no? With a loco that picks up power from all wheels, it should work fine? That's what all my engines are......

(Hoping this is the case!)

[Anonymous]

Hi Gluefinger

wccobb has got it exactly right. Your mainline pack will power anything anywhere on the layout when your yard trackage is assigned to the mainline power pack through the use of a DPDT switch.

There are many examples of how to wire this type of trackage, and how to control your engines, in the book "How to wire your Model Railroad" by Linn H Westcott. The book is old and may be out of print, but you should be able to obtain a copy from Model Railroader magazine.

The book contains wiring diagrams which anyone can read and understand and it is packed full of solutions to wiring problems, including tips on how to keep costs down. There are several examples of mainline and yard trackage wiring with complete 'how to do it' diagrams, and suggestions on how to achieve realistic operation in the make up of trains in the yard and the running of these trains over the mainline.

Mr Westcott spent the greater part of his life providing solutions to model railroad problems and his solutions still hold good today.

Best of luck.

[roadrat]

Insulators, DPDT,blocks,spools of wire,powerpacks etc...etc...
sounds like alot of work for a small layout,
This is just my opinion but that Bachmann EZ command sounds
pretty good for $59 bucks [:D][:D][:D]

bill

[Gluefinger]

Yes it does seem like a lot of work! I hope to make the most of it though...I just can't justify spending more money on decoders, etc. when I already have most of the supplies I need (I just bought two DPDT switches yesterday- one is going to be for a wye track later)

This has become a very interesting and informative thread. Thanks to all!

[nobullchitbids]

Gluefinger: WC's suggestions will work; but, I suspect that, in the long run, you will prefer the flexibility of a little more complexity (which will require a few more toggles). But, before we get to that, a few words on the track plan itself:

Your diagram appears to be showing yard on both sides of a two-track main. A real railroad would try to avoid such an arrangement, since such would oblige switchers continually to cross the main (and tie it up) to get from some yard tracks to others. Real railroads would try to locate the yard either on one side of the main or have the two main tracks temporarily separate so that the yard was entirely in the middle. The yard then could be fed by a lead (or leads) itself connected to the main, somewhat like this:

_____________________________________________________________________\______\________________________________________________________/___
\____________________ \_____________________________________/ /
\ \ \___________________________________/ /
\ \ \_________________________________/ /
\ __________ \ \_______________________________/ /
\____________________\_ \_____________________________/_/

In this arrangement, the yard splits the main, so that both eastbound and westbound trains can be served by it.

Now, on a scratch sheet of paper with the above sketch, number your turnouts starting at the top, left to right: 1;2;3 (eastbound main); 4,5 (westbound main); 6 (yard lead); 7 (yard feed/eastbound arrival-departure); 8 (double slip switch-yard feed); 9 (westbound main); 10 (yard lead #2/westbound arrival-departure; 11 (runaround/westbound arrival-departure); 12 (double slip switch-yard feed); 13 (yard ladder); 14,15,16,17, (yard ladder); 18 (caboose track); 19, 20 (yard ladder); 21 (westbound main); 22;23 (westbound main/runaround).

You now should have a good idea of what the tracks do, coupled to a flexible arrangement for doing it. Conceivably, you even could have a complex multiple movement where a westbound local enters the arrival track and stops, a westbound hotshot enters the #1 yard lead and uses eastbound arrival to park, and a pair of passenger trains, one eastbound, one westbound, use the two-track main to meet. The hotshot then follows the westbound passenger west, and the switcher sets about to break up the local so that its cars can be dealt into eastbound or westbound freights yet to appear.

Just to keep everyone busy!

To use simple d.c. with this arrangement, I would build a panel, on which either an SPDT or DPDT switch allows power to be routed from either of the cabs to any particular track segment (duplicate WC's idea for each segment, e.g. the yard track served by turnouts ## 19, 20). As for joiners, the general rule of thumb is that you MUST have an insulated joiner (or a gap) at every opposed pair of frogs. Thus, for a crossover, e.g. turnouts 1 and 4, you will need a double gap, since the frogs oppose; however, in the yard ladders, you only need a single gap (in the north rail) to isolate these areas and (with proper feeding) NO gaps in the normal frogs of these rails.

How do you avoid shorts? Answer: Properly place your feeders. One pair definitely will go between turnouts 4 and 5; notice this will power the entire switch complex on the Eastern side EXCEPT for the portion of track accessed by turnouts 21 and 22 (these are identical to "crossover" switches and will require double gaps) or the eastbound main.

Another feeder goes before the points of turnout #1(which also adequately will power turnout #2).

The frog at #2 must be isolated from the frog at #3, because they oppose, and this will require a single gap at both frogs in the north (bottom) rail. An SPDT toggle controls the section between these turnouts, with NO gaps needed in the eastbound south rail (this is the COMMON rail).

You may add another pair of feeders west of #3, although only the north connection is essential (I add these extra feeders because wire generally conducts better than rail and therefore extra feeders reduce voltage drops). Similarly, place two feeders west of the points of #9, and notice that these feeders will control the entire switch structure on the western end EXCEPT #23, which again needs the double gap for being in effect a "crossover" turnout.

Put another pair of feeders between #22 and #23, to "liven" this gapped area, and isolate the area between #5 and #6 (a good location to park the switcher when not in use).

Now, here's something which may seem strange: Notice that, for westbound trains, it is the NORTH rail which does not need to be gapped; so, in this area (and I do not know if you have a two-track main throughout), the COMMON rail is not the south rail but the north one! And, if the two tracks finally come together to form a single-track line, notice that, at this point, you would have a common north and a common south rail -- it takes only one more DPDT switch to determine which power pack will attach to it at any one time (the WC solution).

Why use a "common rail" scheme? It is cheaper (the components are less expensive); it allows for power routing of the ladder tracks (which incidentally can be controlled with a big capacitor and a diode matrix wired into the switch machines via single pushbuttons); and, for me, almost as important somewhere down the line, it allows for installation of signals (perhaps with gapping NOT corresponding to the power gaps) and full interlocking of complex trackage. And, since the signals will need their own gapping regardless of whether one uses DCC (and since opposing frogs need to be gapped to prevent shorts, even with DCC), all this work will not be a waste of time should you elect to go to DCC.

One extra word here: If you are going to incorporate a true reverse loop (as opposed to a "dumbbell" arrangement for maintaining double-track illusion), you will need additional extra wiring for the loop, so that you don't end up with a short all the way round the loop. But, that is another issue and beyond the scope of my reply to your posting.

[nobullchitbids]

Well, gentlemen, there is a problem with my diagram, because with the MR Forum set-up, what you see is not what you get, but I will try to redraw it to make it come out right.

[Gluefinger]

I screwed up my original drawing too- should be a one-track line, and I forgot to add in an extra switch. When it was first built, the prototype yard was part of a secondary main, but now it's just a very crappy branch line. There were formerly 10 tracks in it! There was only one siding north of the "main," and the rest was south of it. Since a new yard was built west of here in 1996 and a lot of industry along the line has left town, much of the yard was torn out. I was planning to model this yard as it appeared with the one northern track, and 3 southern tracks.

Nobull, I like your ideas very much! They make me wi***he prototype yard was built with more operations-mindedly [^]...Can I use most of the feeder/isolation ideas for a one-track line as well? I do kind of like the one yard track away from the others though, it throws the proverbial wrench into the well oiled machine.


I went down to the real yard and shot a couple photos- they aren't great, but I didn't wait around for great lighting/composure. In the first shot, you can see the northern siding, the "main" (branch), the one remaining southern siding, and the grassy area is where the former other 8 tracks were (now overgrown). In the second view, you can see the switch where the former 3rd siding came off. (And there were many more)




The weirdest thing about this yard, is the fact that there were no engines or cabooses parked here. Engines were laid over about 2 miles east near the coach yard, and headed up to this (The "Farm Yard") to switch.

Hope this new info doesn't ruin the whole plan.....[sigh]

[nobullchitbids]

I see I have the second-page format here, think that was the problem (I was at the end of the line!).

First, your question: Assume you had a one-track oval. Now, try and hook the two power packs to it. Easy: Run the feeders to the center poles of the DPDT and the end poles each to the respective pack, just like WC advised. Now, let's leave the curves single and cut in passing sidings and yards or industry on the straights. The feeders would go on the curves, before the point ends of the main turnouts. Here, you would have a four-block main (two curves and two straights, which for an internal yard in effect have the north rail and south rail splitting to surround all the complex work in the middle.

Another try at my diagram, this time collapsing into single track (since I have more room):

________________________________________________________________________________________________________________
_______________/ \ \ / / \ ____
\__________\__________________________\_______________________________________/____________________/_________________/
\________________\_____________________________________________/ /
\ \ \___________________________________________/ /
\ \ \_________________________________________/ /
\ \ \_______________________________________/ /
\______________\ \_____________________________________/ /
\______________\_\____________________________________/_/_____________________________________

Now, renumber the turnouts, since I've added a couple. Call the single-to-double turnouts "a" and "b". We then have starting at top left: ## 1,2,3,4 (Eastbound main); ## 5,6 (Westbound main); #7 (yard lead # 1); #8 (to yard ladder); #9 (Eastbound arrival-departure exit); #10 (Eastbound arrival-departure entrance); #11 (yard ladder); ##12, 13(Westbound main); #14 (Westbound arrival-departure/yard lead #2); #15 (Westbound arrival-departure/runaround); #16 (double slip/yard ladder); ##17,18,19,20,21,22,23 (yard ladder); ##24, 25 (caboose); ##26,27 (yard ladder); #27 (Westbound arrival-departure/runaround); ##28, 29 (Westbound main/runaround; #30 (MOW spur).

You can, of course, fold any of the "out in the open" portions to be parallel and therefore closer to other trackage.

Once again: Place your feeders. Two east of "a" points; two west of "b" points (these are the rails to the oval). The four crossovers all need two insuljoiners each, for being opposing frogs, and you also have to isolate with double gaps the opposing frogs to the north (bottom). There is also another pair of opposing frogs at #25 (second caboose-trach switch).

The remainder need single gaps or no gaps, depending on feeder placement. Feeders placed between #5 and #6 will energize MOST of the eastern half of the plant EXCEPT eastbound arrival-departure (need BOTH feeders here, since frogs on both rails, entering and exiting, oblige cutoff of this section). At the other end, you need feeders between #11 and #12, which energizes the west end of theplant, and it is a good idea to isolate the yard ladder from the westbound main, so that throwing a turnout for the main does not place same polarity current on all of your yard rails. The ladder tracks need only a frog leg isolated (one gap each end, north side) and don't worry about the normal settings (the turnout, itself, will take care of that). You test it all on dry run by throwing different combinations of turnouts to see if there is a bad mix (you get a dead short and the power-pack's light goes on). But remember: Some turnout combinations won't occur anyway (unless your yard is big enough to work from both ends at once, it makes no sense to throw a turnout at one end of a ladder track without throwing the other as well, and I just wired mine so they worked in tandem via a capacitor and diode matrix).

So, let's see if this diagram works better.

[nobullchitbids]

Well, another no-go, and I give up (Model Railroader needs to redesign the system so that what we see is what we get).

[rrinker]

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Try this: switch the font to a non-proportional font. I used Courier above and it seems to line up, at least in preview. We'll see after I post this for real.

--Randy

[nobullchitbids]

Sorry, Randy, but font is not the problem. On an extended diagram, the program adds or chops off portions of main line and arbitrarily adds or subtracts them to the next line, moving everything on the next line forward or backward as the case may be, and this error becomes magnified with every additional line of type representing railroad. The result is a mess one cannot anticipate ahead of time.

I just answered an e-mail from someone else who tried but could not decipher the spaghetti. I'll repeat here a portion of what I told him:

The WESTERN end of the plant looks something like this:

south

________________________________________________________________________ EBM
_____________/________________/____________________________________/ WBM
____________/ /_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _/
___________/ /
__________/ / wbm
_________/ /
________/_/_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

WBM

north

&c. Of course, the ladder can have as many classification tracks as fit in the available space. Now, follow the westbound main EAST to the point it diverges to the northeast, around the yard; go straight instead. The next turnout is a double slip switch which connects the eastbound main to the eastbound arrival-departure and the yard, and connects the westbound main also to eastbound arrival-departure and the yard.

Finally, the dotted trackage was not in the original diagram: If the yard be big enough to switch from both ends at once, a western yard lead/drill track is needed to keep the western switcher out of the way of mainline traffic. As for the spur, that is where one might park MOW/fire train, &c.

Hopes this helps everybody a little bit.

[rrinker]

Well that one looked ok.

The problem really is proportional spaced fonts. Lots of the same character often get scrunched together and throw off the alignment. Other forum software has a {fixed} tag which allows you to fully space text and have it all line up as expected, but apaprantly this one does not. Oh yeah, SPACES in proportional fonts are murder Try lining stuff up in a word processor using spaces - doesn't work. Tabs do. Or using non-proportional spacing.

--Randy