Milwaukee’s 2021 Trainfest Cancelled

Group cites uncertainty; show may return in 2022

The Board of Directors of the Wisconsin Southeastern Division of the National Model Railroad Association has announced via its Facebook page that the 2021 Trainfest is cancelled.

“We really wanted to have Trainfest this year; however we think the risks are too great to hold the show,” the Facebook announcement said.

The posting added the organization is facing cost and volunteer challenges with the event, and having the function this year could put future events at risk.

“We are at a point where we should start spending money to put on the 2021 show. Money we cannot recover if the show has to be cancelled. Such a loss would place the 2022 show at risk.

This will be the second year in a row the live event has been cancelled due to pandemic complications. It is too early to tell where the direction of the show will be 12 months from now.”

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HO Scale Vehicle Windows On The Cheap

Have any 1/87 scale vehicles on your layout that do not have windows? Got them at a good price? Don't look that realistic? How many of us have answered Yes, Yes and Yes to these questions (one of the very few times you've answered your own questions when talking to yourself).

If you want to fix this issue cheaply (read as 2¢), take a look at this 9:59 sec video on YouTube. Looks like you have another project to add to the list.

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Measuring Motor Stall Current the Safe Way

Many of us have measured the motor stall current of a locomotive to determine whether the motor needs replacing before installing a DCC decoder. Too much amperage will almost instantaneously fry a decoder if the engine stalls under load.

The procedure we’ve used in the past has been to put the engine on a test track with an ammeter installed between the track and the power supply. Apply full power while holding the engine down to prevent the driver wheels from turning. The peak current measured on the ammeter is the motor stall current. If it is higher than the rated maximum current of the decoder you want to put in the engine then you will either have to replace the motor with a more efficient one or use a higher rated decoder.

Recently, the author came across a different method that is interesting. For those of us who may be math challenged don’t worry this method uses basic arithmetic. 

First you would have to remove the motor from the locomotive. Connect the motor to a 100 Ohm series resistor and twelve Volts. Measure the voltage across the resistor and the voltage across the motor with the motor locked so that it will not rotate. See figure 1.

 

  Figure 1 Measuring points <Updated 07-03-2021>

Here’s that upper-level math we were talking about. Divide twelve volts by the measured motor -voltage. Divide the voltage across the resistor by 100. Multiply these two numbers together and you have the full load stall current measured in Amperes in a safe way.

The reason for doing this is that measuring stall current directly (the old way) may damage the motor. It is a little more work but may save you the cost of a new motor. As the author has said in past posts, your call! 

Thanks to Ken Harstine of the groups.io forum for this new method.

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Digitrax LNWI, UR93/UR92 with DT402D/500D/602D Throttles

There is a lack of good information available today concerning Digitrax’s LNWI (WiFi module) and how it works when used with the UR models and throttles mentioned in the title in various combinations with one another.

Specifically, this discussion will cover the LNWI when used with the UR93 alone and when used with a combination of the UR92 and UR93. For details of the LNWI used with a standalone UR92 and DT402D or DT500D refer to the previous post which talks about this explicitly. Peculiarities with the different throttles will be included as necessary. The LNWI’s performance (WiFi channel number and Loconet group name) was checked with the smart phone android app Engine Driver. This app also served to insure control was obtained by manipulating a locomotive.

UR93 Standalone

The DT602D controlled all three aspects of the UR93, group name, channel number and key (password key) via the duplex menu provided by the throttle. Pressing Update made any changes to the UR93 and also updated the LNWI to the same values (channel number and group name and key).

In order to test locomotive control with the DT402D and DT500D untethered, it is absolutely necessary to update your UR93’s firmware to at least the update dated April 5, 2021. This is available on Digitrax’s web site here. Without this update the throttles cannot talk to the UR93.

Note:
As discussed in this previous post the Author’s DT500D is not able to change the channel number of the UR93 and in this case, his results with the DT402D were completely unpredictable at best (has anyone gotten this to work? Please leave a comment if you have). This may be fixed in a future firmware update but how many resources does Digitrax want to put into out-of-production throttles?

Utilizing the standard Digitrax procedure, changing the group name and pressing Enter will update the LNWI. If the channel numbers between the UR93 and LNWI happen to be different the LNWI will not function properly as shown in the table below. Change the LNWI channel number via its op switches (detailed here) to match the UR93 if you do not have a DT602D to do it.

Note:
The author has been told by more than one individual that newly received LNWIs when plugged into a UR93 will work properly with both different group names and channel numbers. He was not able to reproduce this.

Here are the tests results.

Group Name	Channel Number	LNWI Result
Different	Same	Controlled locomotive
Different	Changed to different	No control
Changed to same	Changed to same	No control until LNWI was repowered then was able to control locomotive

 UR92 Standalone with a DT602D Throttle

The DT602D was able to make any and all changes to the UR92 and attached LNWI via the duplex menu.

UR92 and UR93 Combinations

Note:
The author does not recommend you utilize a UP5 panel to connect and make adjustments to UR92/93 combinations. During testing he plugged a 602 and a 500 throttle into the same UP5 and received different results on their displays. This is obviously due to timing differences between the throttles and URs and which UR answered which DT. Plug the throttle directly into the UR you are manipulating.

Utilizing a DT602D to update a UR93 via the Duplex menu will update connected UR92s and any connected LNWIs to the values specified in the menu when the Update button is pressed. In the author’s tests he found it may be necessary to update more than once. Regardless, give Loconet a little time to catch up.

A DT500D or DT402D throttle plugged into a UR92 to update values will also update an attached UR93 and LNWI as long as the Enter key is pressed to complete the update. Just plugging it in and changing values will not update anything.

The author swore he would not “go down the rabbit hole”¹ of plugging differently configured UR92s and UR93s into a properly configured circuit to see which one would override the other (if at all) and the resulting problems (or not) with the LNWI. What has been accomplished here so far took a lot of time away from family. Volunteers???

Recommendations

Follow the instructions in the section that contains your configuration (this includes the prior post here) and you should be set and ready to go.

The author hopes this research clears up a lot of misunderstandings concerning the LNWI and its workings with Digitrax’s other components. With the newer products that have recently been put on the market along with the older components still in use, and they will be for a long time (how many of us still use a DCS100?), things can get a bit complicated. The author can only hope this helps.

In the future, the author plans on presenting monitored Loconet printouts with the various throttles and URs to possibly show timing between the various components and what that may demonstrate (if anything).

1 This is a well known term in the computer field meaning a complexly bizarre or difficult state or situation conceived of as a hole into which one falls or descends.

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