Large Scale Central

USAT Hudson Conversion

Modeling Motive Power
#1

I bought a used (but never run) Hudson in SP livery a while back, and finally dug into it this week. I’m installing AirWire, and integrating the stock sound (Phoenix 2K2) and TAS smoke setup.

I started by totally gutting it. I unsoldered all of the wires from everything and yanked all the incandescent bulbs, wiring, and stock circuit boards.

The conversion will consist of a 18 V, 10 Ah Li-ion pack in the tender, connected to the locomotive through the stock cable. I’m doubling up conductors in that cable, as they are 24 or 26 ga (a little small). Four of the 6 will carry battery voltage/ground, and the other two will be control lines for the backup light and markers (though I can’t imagine an operational scenario where markers would be needed). Below is the connector in the locomotive with the doubled power connections.

I rewired the two switch panels to provide separate power to the G3, sound board, and smoke unit. The second pole on the sound switch (yellow wires) will interrupt the DCC signal from the G3, as that’s its primary source of power. The “lights” switch is wired for battery voltage, but not currently used. Here is the sound/switch package, ready to go. The blue wire is for chuff and will get attached to the sensor when it’s in place.

The G3 will mount on a custom bracket, just forward of the stuff in the photo above. The bracket uses two of the screws for the speaker enclosure cover, and one of the posts from the stock circuit boards.

I’m held up at the moment waiting for a speaker to arrive (FRS7, naturally). One other detail I finished is the LED conversion for the firebox. I used 3 mm orange LEDs. These will get the “flicker” effect from the G3.

That’s all for now!

#2

This will be fun to follow. It looks like you’re off to a great start…as you always are. Mark

#3

Eric

The TSA unit just wasn’t up to what I was looking for…

I went with a Zimo smoke unit ( modified old Aristo unit )

https://www.trainli.com/all-about-smoke-284/pl-92101-p-1258

Train-Li sells them , with a Zimo decoder it preforms close to prototypical .

Dan installed the set up.

Sean

#4

Thanks, Sean. I have in mind upgrading the smoke unit in the future, but just want to get this thing running for the time being. I was looking at the Massoth units. They look pretty nice.

#5

#6

That looks great, Sean. So is that being triggered by the sensor on the axle?

#7

The zimo runs the heater and fan. You can trigger with sensor, or do “auto chuff”… in any case the Zimo handles the power for the 2 parts of the smoke unit.

Greg

#8

The Hudson is almost back together. A couple of details to finish, but it runs, makes noise, and smokes.

The FRS-7 barely fits in the loudspeaker enclosure. I had to grind the tabs off the sound board holder to get the lid on, but it isn’t going anywhere.

Here are some photos of the finished interior:

The protoboard serves three separate purposes. On the left are optoisolators to drive the sound and smoke units from the chuff sensor. The third optoisolator also allows for the G3 to trigger the smoke from an aux output. I have in mind using this for steam release, synced with sound. The optoisolators are driven with CL2N3s.

In the middle the ribbon cable connects the outputs of the G3, through CL2N3s to headers for the headlight, cab light, and front markers.

The right side of the board contains an Arduino Pro Mini, 2N7000, and CL2N3, all dedicated to creating the smoldering effect for the firebox. I tried the “random flicker” on the G3, but it sucked. Here’s what the effect looks like, using 5 orange LEDs in place of the original bulbs:

I assigned the “lights” switch to the flicker so it can stay running with everything else turned off.

Meanwhile, in the tender, I printed this battery tray that fits into the recesses in the floor.

The bracket with the charge jack and circuit breaker will be attached to the battery tray. I haven’t gotten to that yet.

#9

Looks nice Eric. So is it going to be able to pulse the smoke?

#10

Yes, it kind of works. It pulses at first, but then it just goes on full for a few seconds. I’m not sure what the story is. In any case, the TSA unit is pretty underwhelming.

Here’s what it’s doing:

At 0:06, the fan just goes on and stops pulsing.

#11

yeah I can hear the fan in the video. I am sure you can figure out the logic to fix the fan staying on but in regards to the unit itself doesn’t seem like it has a very powerful fan to drive the smoke out in the first place.

#12

I might get one of the analog Massoth units and give that whirl.

#13

Massoth is not too super, best is direct control of the heater and fan and lots of current to the heater.

Have you seen the Massoth in operation?

Greg

#14

Greg what is your recommendation?

#15

Tain-li 's smoke unit is only $45

https://www.trainli.com/accessories-cables-smoke-326/pl-92101-p-1258

#16

The Train-Li unit requires a driver for the fan. The more I dig into this, the more I want to develop a driver. Lots of possibilities. Dynamic braking for crisp chuffs, different accel vs. decel behavior, etc. There is a product called SUPER-CHUFFER that does some of this, but it tailored to a specific O scale control system.

Im also looking at the MTH units.

#17

I pulled the thermistor out of my TAS unit, and the chuffing behaves as intended now. The thermistor was resting on the heating elements, and was scorched. I don’t know if it’s supposed to actually touch the elements or not. I think the microcontroller was seeing this as overheating, and turning on the fan to cool it. In any case, the output is still lame.

#18

Eric Reuter said: In any case, the output is still lame.

I agree …

#19

Sean: what are you using to drive the Train-Li unit? A Zimo decoder?

#20

Eric Reuter said:

Sean: what are you using to drive the Train-Li unit? A Zimo decoder?

Yes

Dan Pierce did my install…