Thanks all.

I'm thinking a DPDT switch plus a "guard track" between the main and programming spur, that is longer than my maximum shorting length, and is unpowered when the switch is in the programming position. 

I should probably check whether the switch is break before make, or perhaps use one with a center-off position, just to be safe.

I'm planning a conversion to DCC and I have hit an issue.  I want a programming track that's a spur: a switch form the main line, and and double-gapped spur that's wired to the Prog A and B terminals so I can drive a loco onto it for service mode programming.  Despite the vendor's manual showing just this, their tech support people advise strongly against it, saying "[y]ou can easily damage the program circuit if you have the main track set to Rail A and Rail B and the siding set for the program circuit and the loco creates a bridge between the two circuits." 

So, I'm thinking of a design that would obviate this danger, and I need to know over how long a track distance a Bachmann loco or track-powered car will short the rails - which I've called the "shorting length" in the title of the post.

Clearly a wheel bridging a gap will short the rail, but if this could be mitigated in some way, what's the next distance?  On my BBH 4-6-0's, the leading truck picks up power, as do the drivers, so it would be from the leading wheel to the last driver - I don't have one handy to measure now, but you get the idea.  For a passenger coach with track powered lighting, and both trucks fitted with pickups it would be first axel to last, right?

Any ideas?

Thanks,

jv

Hi Bill,

There's a seller on eBay who has them.  He says they are form store displays.  All are Baldwin 4-6-0 White Pass and Yukon Anniversary units, sold with a tender or without, and tenders sold separately.  I just checked, he as one left with tender, three loco only and three tender only.  I think the price is very good - used to be cheaper, but he raised it! 

Cheers,

jv

Thanks, great.  LEDs are on the way.  Don't know what I'll do with the extra 98 LEDs!

I should make a parts list, of what else I need.  It's mostly wire and connectors, and a weight.  I don't have a smoke unit, but I rarely use it on the existing loco's because the smoke is so wimpy.  

I've found that on my Anniversary D&RGW that the two wires connecting the loco to the tender are so stiff that they cause derailments!  They are also way too long.  

I wonder if there is some prototype hose feature or something that could be simulated with the wires?

Thanks Kevin.  Do you know the ideal diameter of a round-top LED that would fit the reflector hole?  I just ordered a bag of 100 5mm, warm-white LEDs- very cheap, on speculation that they'd fit.

I checked allelectronics, they seem to have mostly connectors with leads attached.

For weight, I have lots of lead, and I can cast, so I will probably just make a pattern and cast a couple in a sand mold. 

I thought folks might be interested in this project, and maybe even help me out of tight spots, and sourcing components, and so forth.

I purchased an Anniversary 4-6-0 dummy loco and tender; actually, two sets.  They are White Pass and Yukon, and both are number 14 (unfortunately).  They are beautiful.  I was really amazed at the beauty of detail and execution, never having had an Anniv. unit before.  Now I have these two, plus a complete Anniversary D&RGW "Bumble Bee."

The dummy units are complete outside, but empty inside, literally nothing is present that is not visible externally. 

I am going DCC.  I purchased a Tsunami TSU-1000, and I will find out if it can handle the 4-6-0 on level track.  I think it will. 

I was fortunate in that Bachmann parts is selling generation 5, Anniversary chassis on sale this month (and last) for a very reasonable price. 
I have purchased two, both with Walscherts valve gear.  The dummies have the much more simple Stephenson valve gear (or no valve gear, as far as I can tell); so I have choices.

I have separated the chassis and shell, and lost a piece of piping in the process - part number MCT31 (right side).  Oh well! 

I have removed the connecting rods, disassembled the drivers, and am preparing to swap the wheels and wheel covers to the working chassis. 

I found a speaker that will fit the tender.  I will likely fabricate clamps to secure it.

I need:

LED bulbs for head and tail lights;
a weight for the chassis;
connectors and wire, for the internal connections, and the loco to tender connection.

I also need to decide if I'll swap the leading truck wheels, or swap trucks and pickups and wiring.

Comments appreciated!

jv

Thanks, Stan.  I'm looking forward to reading the draft.  I have concerns; those .025" square pins are marginal for LS, for current rating.  I've seem them conservative rated at 3 Amps max, 'though some vendors rate them higher, as high as 6.3A, with constraints on number of current-carrying pins per housing or header. 

This brings up another issue.  I see in the existing NMRA standard a distinction among DCC interfaces according to scale.  For example, the 8-pin interface in S-9.1.1_Connectors_2013.07 is limited to 1.5A, and aimed at "medium," i.e., HO scale, yet one can purchase a 4A HO decoder; and the "large" at 4 Amps seems marginal, not for me, but for what I've heard folks talk about.  The definition of "peak" is missing, too. Oh, well.  It's easier to be critical than correct, as they say.

Thanks again,

jv

Thanks Stan and Hunt.  I read the doc and all the child docs that Hunt's link points to.  Very interesting.  I confess I have only learned of this now, but I can't detect that there's a single decoder available that actually plugs and plays.  Am I missing something?  All of the ones documented require at least one of trace cutting, soldering, component additions, and so forth. 

Stan, when you say "the NMRA did indeed create a draft standard for an interface for Large Scale" I take it to mean it never made it to publication as a standard; is that so?  Is the draft available?

If the draft isn't available, can you say what the motor current maximum is for this interface?  Other electrical characteristics?

One curious thing, Bachmann says "first Large Scale locomotive with totally isolated electronics, which allows for easy installation of the control system of your choice" and then has pins on the interface for locomotive ground and locomotive positive.  What could these be?

Has anyone else implemented this?

I would prefer a connector-based standard that didn't require such a wide header; 12 pins presumably on 0.1" centers makes for a cable-mounted header about 1.5" wide - tough to snake through spaces.  And, the entirety of the keying feature is implemented with a blank position, requiring the PCB to implement the keying feature.

Thanks,

jv

Thanks all.

BTW, Kevin, it's http://www.allelectronics.com, without the hyphen.

jv

Hi Jerry,

I'm sorry if I offended you and any other NMRA volunteers and supporters, no offense was intended.  I am familiar with standards work, having done my share professionally with the IEEE, and I know it can be a tiring and thankless undertaking. 

Perhaps short shrift was too negative a term.  It's only that I'd like to have an 8-pin standard for large scale just as HO has, and I don't think it would have taken more than a day, or even an hour to jot something down, or even to just declare a an abstract 8 pin layout and assignment, without even choosing a connector.  Choosing a connector is among the most contentious things a standards body can do, so I say just choose something and move on.  The primary issue is current carry capacity, and this is made more difficult still in small, multiple-contact connector housings, as opposed to loose wires, for thermal reasons.  But even so - I'd like a standard. 

And ideas on a good connector for an LS version of the NMRA HO connector standard?

jv

I know there's an NMRA standard for decoder connectors and color codes, but I feel large scale gets short shrift from the NMRA.  For example, that only standard I can find covering large scale in-loco wiring with DCC is for motor and track connections only, unlike the HO scale 8-contact standard.

I'm venturing into adding decoders and rewiring some things, and I'd like to do it in an easy, reversible, modular, sensible way.  For example, my generation 3 BBH Pennsylvania 4-6-0 headlight and smoke unit wiring was connector-ized to the chassis via a pair of .025" square pins and mating connector shell and receptacles.  Great, that's a start! 

I would like to able to switch from DCC to analog, swap decoders, etc., via a good connector system.

I would sincerely appreciate your views and experience on this.

Thanks,

jv

Thank you again, Kevin, for your thoughtful reply to this, and to my other annoying posts!  You can probably tell I'm new here, and I've re-entered this wonderful hobby after a near lifetime hiatus, using my grandkids as the rationalization. 

You are right, I think, using a decoder is probably overkill.  A switch will suffice, 'though it's less fun!  It would be awesome to be able to get them to go on serially as if someone was walking down the car lighting them. 

I hear you regarding the aesthetics of the incandescent bulbs in the coaches, but I pulled mine, in one coach so far, because first, I couldn't unscrew the burnt-out one, there was a drop of lacquer applied, apparently to keep it in!  And, I like the long life of LEDs, since the coach must come apart to replace an incandescent bulb.  We'll see, I found and ordered the warm-white variant of the LEDs for which I supplied the link, a 16.4' roll of tape with 300 LEDs for $8, and the tape is self-adhesive; tough to beat!  We'll see how it looks when dimmed-down.  I'm assuming they consume less power than the bulbs, so as long as I continue on the 9V batts it's a win, too.

I've done some research on wooden passenger coach lighting and found that for the era of interest the dominant coach lighting technology appears to have been Pintsch gas.  Fascinating!  Here are a couple of links:

http://www.rypn.org/forums/viewtopic.php?f=1&t=28925

https://books.google.com/books?id=A0k1AQAAMAAJ&pg=PT48&lpg=PT48&dq=%22A+Perfect+Light+is+a+Luxury%22&source=bl&ots=o-qyMLXW7b&sig=HELFgh-ktS43g8gDX8nwJkLIUY8&hl=en&sa=X&ei=PYcNVbLWGoLUgwT4-YHQBQ&ved=0CCMQ6AEwAQ#v=onepage&q=%22A%20Perfect%20Light%20is%20a%20Luxury%22&f=false

It would be interesting to know the color temperature of Pintsch gas lighting, and more detail of how many ceiling lamps in each type of coach, and the outside venting and plumbing details.

I am going DCC, and have a string of three Pennsylvania passenger coaches I'd like to convert to DCC track lighting. 

To start, I have a coach and an observation car that came in a set, and a combination baggage coach car that I purchased separately.  All are 9V battery, incandescent lit.  The first two have plastic wheels, the last metal wheels.  All of the trucks have the provision for the spring-loaded electrical pickups, but they are unpopulated.

I have considered a few options. 

1. Electrical pick-up.  The easiest thing to do would be to purchase (eBay) a few sets of the brush, tube, spring contact sets for these trucks.  I wonder if I should do both trucks of each car?

2. I've considered wiring just one coach with contacts and a decoder, and wiring them together with what would look like brake hoses.  This way, one set of contacts and one decoder for the three coaches.

3. Decoder choice: I was thinking that I can use something like the Digitrax TL1.  I am brand-new to DCC, and I'm in a bit of a fog over this.  It says that the TL1 can be turned on/off using  F0, F1, F2, F3, or F4.  Can I set the address of this decoder to the same address as the mobile/sound decoder in the locomotive so that I don't have to switch addresses on the throttle to turn the lights on and off?  Is there a "standard" function number for coach lights?

4. I've already converted one of the coaches to LED lights, using a strip of LEDs:

http://www.amazon.com/gp/product/B005GL5R56/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

They are kinda bright running directly off the 9V battery, and a bit too "cool," I think.  I assume these wooden coaches had oil or incandescent lamps, and would be much warmer, but I'm no expert on the prototype.  I will dim them when I install the decoder, which brings up an interesting question: what's the voltage of a function output?  What type of output is it?



Thanks,

jv

Well, I guess I could do that easily - just bring the voltage up until I see the error lamp start flashing?  (I have a really good laboratory DC power supply).  I wonder if Soundtraxx would replace it for too low a trip point.

Thanks Hunt.  Have you experienced these shutting down for over-voltage at less than 22V?