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Runaway Train!

I was hoping that if people gave up on the throttles that depended on other, more powerful throttles, to acquire locomotives, this would become a minor issue.  Alas, the Digitrax wireless throttle brings this headache to their most powerful throttles. It is not the throttle's fault. It is operator error.

Their throttle manual tells you how to acquire a runaway train, so I won't go into it here.

What I will discuss is what's happening to you and how to minimize the problem.

INFORMATION #6-5:  How Come I Keep Losing My Locomotive?

While the wireless throttles themselves don't cause the problem, it's just extremely aggravating because you have to go back and plug into the network.  It's especially aggravating for me since I have to go back into the garage to reacquire the locomotive for my garden railroad.  This aggravation alone will make two-way wireless very desirable for me.

I will not pretend that I have all the scenarios here and not all the recovery procedures.  To be sure, you need to know how to steal a locomotive back.  So get your Digitrax manual out and learn it.  But how do you lose your locomotive in the first place?

I'm a fast button pusher.  That gets me into a lot of trouble with these throttles.  Break yourself of all these habits:

1.  If you are operating a function and you want to get out of the function mode, be sure to press the Mod/Sel button.  Do not press the Sel/Set button.  What will your next stupid mistake be when you find that the Sel/Set button does not get you back to the throttle display?  You press the Mod/Sel button because you know it was one of these two buttons that gets you out of the function display.  But pressing Sel/Set followed by Mode/Disp just did what?  Bye, bye, locomotive!  You just dispatched it!

2.  I have DCC controlled turnouts in my garden.  So I'm pressing the Mode/Disp button frequently.  Get your hand anywhere near that Sel/Set button and you will soon lose your locomotive when you go to flip that turnout.

Look at the display when you are pressing buttons.  I tend to press buttons because I know what the sequence is.  But if I get ahead of the throttle, the locomotive is gone.  This throttle is not a 600 MHz Pentium; you can get ahead of it.

In reading Digitrax's manual for their newest command station/booster, the DCS240, they admit you can turn a command station into a booster, but they have heavy recommendations against doing this. One of the problems could be runaway locomotives. Apparently, it has a few bugs. On my previous railroad, I did have an industry served by a command station I was using as a booster and we had frequent runaways there. We could never figure out why. So, I, too, join Digitrax in recommending against doing this. If you choose to do this, you've been warned!

SUGGESTION #6-1:  Disable a Decoder's Standard DC Capability.

If not disabled, a decoder will switch to standard DC analog mode of operation in the absence of a valid DCC signal. If your layout is having "technical difficulties" a locomotive's decoder may not see its DCC signal. There are situations where this will cause a locomotive to "runaway."

If you are experiencing runaways:

1) Change CV 29 to 2 for decoders using the 2-digit short address. This prevents the decoder from going into standard DC analog mode in the absence of a valid DCC signal.  There are other values for this CV.  For example, I use 22 for my 4-digit long address FX decoders.  Consult your decoder manual and pick the value that is best for you.

2) Read my section about booster networks.

The new Chief set from Digitrax has an auto shutdown mode if a DCC command signal is lost.  So you may not have to do this with their Chief set.  As a manufacturer, they want and need to sell trouble-free analog capability.  As the end user, I'd still disable the standard DC (analog) mode if you don't need it.  It's just an extra degree if insurance against a runaway.

Note:  There are good reasons why you may want the DC (analog) mode to be turned on.  Then this option isn't for you.  I won't get into what those reasons are.  You will know when you need to turn this option on.  Simple example:  You want to be able to run your loco on a friend's regular DC layout.  You need this option on — at least while you are at your friend's house.

SUGGESTION #6-2(D):  How to Rescue a Runaway Train.

Note!  The new Chief set and the DT100 throttle have a procedure for "stealing" a runaway train.  See you Chief manual and disregard the following which pertains to the Big Boy set and DT200.

The first time I heard about this, it sounded like black magic. I like to understand things. It makes it easier for me to remember what I'm supposed to do when I'm frantically trying to rescue a locomotive.

Before we start, here's the situation.

Someone unplugged their BT-2 that either had no battery or it was low. When plugged back in, it doesn't remember that it was supposed to communicating with the now runaway.

The command station knows that the locomotive is assigned to a throttle. So it won't allow another throttle to control it.

1) With a DT200, DT100, or presumably with the yet unreleased DT300, and a good battery of course, dial up the address of the runaway.  You will get an 03 in the right side of the display.  This means the train is assigned to a throttle - the one that no longer can control it.

2) With the left digits flashing, unplug the DTwhatever throttle. The throttle will remember that the last thing it was doing had something to do with the runaway.

3) Plug the DTwhatever back in. It, and the command station will think it was the throttle assigned the runaway. Get it under control and press the Sel/Set Dispatch key to redispatch to the BT2 — after it gets a new battery.

SUGGESTION #6-3(D): Don't buy BT2s. Buy only DT400s, DT300s, or better.

BT2s are unable to rescue runaway trains. If you have a bare minimum of DT200s, that one or few operators will have to be interrupted to rescue trains. Hopefully, if you follow the other advice listed here, you won't be rescuing trains very often. Hence, this is a suggestion, a non-wiring one at that, rather than a recommendation.

You will want DT200s or better if you want to use DCC controlled turnouts.

SUGGESTION #6-4:  Turn Down the Throttle Before Adding A Locomotive to the Track.

In testing locomotives, I occasionally put on the track and had it take off.  It was my fault.  The throttle was advanced from a previous test and the train was simply doing what it was supposed to!  Don't forget to turn down your throttle when testing new locomotives.  Remember, most are preprogrammed to have a default address!


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