Actual Locomotive Throttle as Layout Control?

[Rudy Garbely]

Well, here's an interesting project for everyone. I am not an electrician by any means, so I need a bit of help with this. I just *ahem* "inherited" the entire throttle/reverser mechanism from the control stand of 1:1 scale CN M420 #3573 (which was just scrapped). By "inherited," I mean my boss told me "hurry up if you want to take anything, the scrappers are coming in an hour."




I'm trying to figure out how to rig this up to my layout as a controller with variable speed control via the throttle lever and a built-in permanent momentum feature, a working reverser (with the neutral position turning the power off), and maybe an electronic braking feature similar to many MRC power packs.

I'd like to use the existing electrical contactors that are present in the back of the throttle combined with resistors to somehow make a realistic speed control (while using the momentum to create a realistic lag when throttling up). With the electronic brake, I could probably turn this into a fairly realistic operating throttle for my layout.

Here are the specs and some photos of what I'm working with, showing which contactors are activated when the throttle and reverser levers are in different positions.

Reverser mechanism (three contactors)
Neutral - no contactors activated
Forward - 1 & 3
Reverse - 2 & 3



Throttle mechanism (eight contactors)
Idle - 1 & 7
Notch 1 - 1 & 2
Notch 2 - 1, 2, 3
Notch 3 - 1, 2, 5
Notch 4 - 1, 2, 3, 5
Notch 5 - 1, 2, 4, 5, 6
Notch 6 - 1, 2, 3, 4, 5, 6
Notch 7 - 1, 2, 4, 5
Notch 8 - 1, 2, 3, 4, 5
Notes: Contactor #8 is never used, #7 is only used in Idle, #1 and #2 are used in every powered notch



Does anybody have any idea how to do this properly? I don't really have a clue where to start... I just know it will be really cool when I figure it out!

[Rudy Garbely]

Anything guys?

[Randy Earle]

There used to be a video on Youtube where a guy used a control stand on his layout. I don't remember who it was, but he modeled Conrail.

[Randy Earle]

I found this one Rudy. The guy made his own control stand.

[lyled1117]

Just to be clear, you say the different contactors are closed under the different notch or direction positions, but none are bridged (shorted) together in any position, correct? It doesn't appear that can happen from the photos. It looks like all the different contactors are independent except for the "A" and the "B" which are bridged by the wire connector on the right of the 3rd photograph. Also, do your numbers correspond to top to bottom arrangement ("S" = 1, "M" = 8) of the contactors, or bottom to top?

Lyle

[Mark R.]

Is this for a DC or DCC conversion ?

Mark.

[iomalley]

Mark has a good question, because if its just DC then a simple rheostat driven off the throttle would work. DCC? No idea...

[Mark R.]

If you are using DC, you could build a basic DC throttle yourself. You would need one with at least some kind of built in momentum. Instead of a variable throttle, you would use series of resistors connected to the various inter-connections of the throttle. Each notch would progressively reduce the resistance in the throttle settings. The momentum would be required to smooth the jack-rabbit jumps between throttle positions.

Just scratching the surface, but it should be do-able in DC. DCC ? - I'm with Sean .... wouldn't know where to start ....

Mark.

[emd16645]

I was thinking to get it work with DCC would require some sort of computer based throttle interface, what that would be, I don't know as I'm not knowledgable on computer controllers.

[Rudy Garbely]

It's for DC. DCC is unfathomable to me for this kind of thing!

The contactors are not bridged in any way, but they could be. That one wire is just left over from the original control circuit.

Yes, my numbers run top to bottom. Probably should have just used the letters that are on there, but I wasn't sure how well they'd show up in the photos.

If the contactors worked in some kind of patterned sequence, it would be easy to figure out. But they don't, so I'm trying to figure out how to make it work. I think a rheostat isn't a bad idea if I can figure out a practical way to mount it to the throttle. Still need some kind of built-in momentum feature, and probably a braking feature as well.