DC Knowledge sought

Model Railroader Electronics and DCC
21

Fred, thanks for helping to clarify some of the points of DCC to me. I really find all the doodads interesting in concept but the execution at this point requires more patience than I have. I see far too much frustration displayed on this forum in regards to DCC to regard it as anything but a distraction. The tethered throttles I’ve seen that feature walkaround capability all use a capacitor to hold speed for a given time and a latching relay to control direction. I have no desire for sound other than that the train makes. (Actually, I’ve given thought to modeling electric locomotives just for the “realism”.)

I’ll keep you posted about any electronics I build, just for fun, and if I have questions I’ll bug you, Chuck, Sheldon or one of the other generous lads on this forum.

Harry, Harry, Harry…Boy did you ask the slowest guy in class or what? Seriously, some of the other guys posting replys to my initial question are full of good advice due to their experience levels. I will tell you though, that you’re likely to get a lot of advice to not go with a 4 x 8. As I’ve mentioned to some others, www.layoutvision.com is Byron Hendersons site. He’s a pro layout designer and has some really thought provoking alternatives to that traditional shape. He provides some analysis so the reader can understand the limitations of the 4 x 8 and see the rational behind his suggestions. This is a hobby with fascinating alternatives available and one of the most helpful things is the enormous amount of info available so we don’t have to re-invent the wheel. Unless we want to (see my original post). Have fun and use the heck out of the web to get info.

Lou

22

“DCC Ready” is an industry joke. The way it’s (mis)used in the industry, you could say ANY engine is DCC ready because you can put DCC in anything. DCC Ready can mean anything from “it will take you longer ot get the shell off than to instalol the decoder” to “if you cut here and here, and solder wires there, you can install a decoder”. DCC Ready does not mean it has a decoder in it, so it will work just fine on DC.

Worth the price? Depends on what you want to do. Have full control of sound locos? Pretty much need DCC for that. Want to run just one train around a small loop layout? Don’t need DCC for that. DCC doesn’t have to cost all that much more than a GOOD DC system (by ‘good dc system’ I don’t mean the train set special power packs, which these days go for as much as $50). I see way too much overkill when people get DCC - if you don’t plan to have more than 3-4 locos running at the same tiem you don’t need a monster 5-10 amp DCC system.

–Randy

23

The throttle units I built up are based on an article in the January 1986 Model Railroader. This is a truly DIY throttle that is set up for memory and walkaround, meaning you can accelerate your train, disconnect the controller while the train is running, and plug it in at another location around the layout. The actual throttle itself is under the layout, all you have is a small handheld control that has 5 buttons and an LED on the front, and four resistors and a diode inside. On the club layout we had six throttles, and any of them can be plugged into any outlet. The connection I used is a 25 pin D-subminiature, a common computer connector. Each throttle requires 4 wires, so Cab A is pins 1 thru 4, Cab B is pins 5 thru 8, etc, any control unit can be plugged into any outlet. The handheld unit has only the four wires for that cab attached, and the jacks on the layout have all 24 connections run to the throttles.

24

I don’t think you need to change the whole circuit board to fix the GP15. It may well just be a RF filter circuit like on the Bachmann locos that is causing both problems, poor slow starts and the lighting.

If you can trace out the circuit, look for a capacitor right across the motor leads. If you find one, simply remove it. Often these circuits are tuned to a frequency close to the pulse frequency of the TE. This causes the motor to see the TE signal as pure DC, not the puleses, so this could effect the lighting and the starting speed/voltage of the motor.

I have found this to be the case on a number of locos, vertually all Bachmann locos and several recent Intermountain FP units.

On some locos the difference is small/none. On others, the improvement is dramatic. The Bachmann Spectrum 2-8-0 in particular showed great improvement in slow speed ans slow starting after removing these capacitors. Typically known for not being a great “slow speed” loco, mine now start and run smoothly at or below 3 SMPH. And in the case of this loco, the improvement was noted on both the TE and on conventional DC power packs.

Hope this helps.

Sheldon

25

Tom,

This is one of the throttles I had been interested in. The disposition of componentry sounds like the walkaround throttle I’ve been considering. I assume that buttons on the handheld are used for speed control. Do you find buttons as convenient to use as a rotary potentiometer? Does the MR article give the complete build instructions in one or is it spread out over months? Would the components still be available? Before I commit to build the one I’ve got picked out I’d sure like to see this one. I don’t have a problem ordering back issues for a project like this but I want to make sure I’m not drillin’ a dry hole first.

Lotsa questions, thanks,

Lou

26

Hi Lou

In case you are still around , here is a link to Andy’s Book. Only partial but might be a help…

http://tinyurl.com/ycwdl4j

A lot of links on model railroad wiring below.

http://tinyurl.com/y8jxlky

Rich

27

Lou,

The Aristo Craft Train Engineer throttles use push buttons as well. I did not know if I would like that at first, but after a few weeks of testing one, I have come to prefer it. It does take dome getting use to, but once you get it, it really works well. In many ways it it more like the controls of a real locomotive, steam or diesel.

One feature that is built into the Train Engineer that may be possible with the throttles you are looking at is auto ramp down/ramp up on direction change. At any speed, if you change direction, using the currently set momentum rate, the throttle ramps down to zero, changes polarity, then ramps back up to the previous setting. This is great for slow speed switching even with the momentum set at zero. It turns three commands into one and results in very smooth operation.

So anyway, I hope this helps with your questions about push buttons vs rotary.

Sheldon

28

The components of the throttle part that goes under the layout are mounted on a 16 inch piece of 1 x 6 lumber. Each one has its own step down transformer making them a stand alone control, what you load on the other ones has no effect on the one you’re using. I have them plug connected so they can be easily removed for repair or troubleshooting.

The handheld is small, and I’ve used them so much, I usually hold them by my side or even behind me while switching. The buttons are (E) emergency stop, (F) forward, (R) reverse, (A) accelerate, and (B) brake.

The article was published in that single issue, and the components should still be readily available.

29

Hi Guys,

Rich, I have the first edition of Andy’s book. It’s a great primer and constant reference. In fact some of the stuff he talks about in the section on throttles whetted my appetite for more, which led me here.

Sheldon, that ramping feature sounds tasty! Does it take practice to get the timing right as to when the switcher reverses? I know with my low-buck railpower 1400, if I focus on the closure rate I can get cars to couple without even rolling backward. That power pack isn’t designed for hand held use and it’s clumsy to try and one hand it. That 3 moves in 1 effect I like.

All the throttles I’m looking at are pure schematics with only a bare suggestion of enclosures. The walkaround units use 4 wire cables like phone cable/plugs. The handheld unit only contains a potentiometer, reverse switch, leds, and a few resistors. One version has additional switches for a “scaling” feature for the control pot. It allows you to slow down the response for yard work, then go to a more aggresive response for the main. Another has a single unit throttle/reverse control (clockwise from null = faster, counter-clockwise = slower, null stopped) which seems to be a “poor mans” version of the throttle you describe.

I plan on making my own enclosure as ergonomically sound as I can. I’d really like intuitive, one handed use.

Thanks again to all of you,

Lou

30

Lou, I know you are interested in building your own, and don’t think you need or want wireless, so I have not tried to steer you in my direction up to this point.

However, as you tell us more, you may want to take a look at the Aristo Train Engineer before you make up your mind.

It is wireless, 27 Mhz radio. The hand held transmitter is very one hand ergo friendly with only five buttons for normal train control. They are: accel, decel, direction east, direction west, emergency stop.

The base unit has the actual throttle circuitry and can be programed for various momentum rates. Coupling does take a little practive, but no more than with a knob, just a little different.

At any slow peed, simply changing direction results in a smooth controlled stop, a slight pause, and smooth accelleration back to the previous speed. This can obviously be used for uncoupling with Kadee magnets or for spoting cars in Kadee “delay” mode. Even the emergency stop is a rapid ramp down so at a slow speed it is a controled, realistic stop.

The accel and decel functions of the Train Engineer are smooth, controled and have some “delay” even with the monentum set to its “minimum” setting.

You shoud know up front, the momentum features are not ajustable from the handheld and are not easily reset for each loco - with the version I use. With the newer locos on the market, I have never felt a need for individual ajustment of momentum/braking effects.

But there is a newer version that allows more advanced programing from the handheld. It is the new Train Engineer Revolution. Actually, I have one of these new ones but have yet to try it on anything or learn about all its features or their implcations for layout based control.

All the Aristo products are designed to allow both trackside control for smaller scales and onboard control of

31

l have built this throttle. http://www.awrr.com/throtl8.html. I like the operation and the designer answered my emails when I had trouble with it. One thing I would add is a circuit breaker on the output of Q2. I have blown a few Q2’s with a short.

32

pe700, that’s the one I’m thinking of building. What amperage breaker would you use, just shy of the max. output of the throttle? I’m glad to see the designer is available, there’s nothing like getting info straight from the source. Did you have any trouble sourcing the parts?

Sheldon, I’m going to have to take a look at Aristo-Craft’s site. At some point in the future I may, as you indicated, desire to use a radio throttle and I’ve heard their name for a long time.

Thanks

33

Lou, just so you know, because they are very large scale focused, Aristo Craft’s product info does not explain much about using the Train Engineer in HO.

So, please feel fee to ask on here, or send me a PM if you have questions they don’t seem to answer.

Sheldon