Hi! We're about to embark on a huge model railroad for our club here in San Diego. The railroad will be double track, and a little over 15 miles long. We've been talking about various DC block control methods, but I'd like to see if anyone has any great ideas. So far, we've looked at rotary switches, but they have the annoyance of turning on all the other blocks for an instant as they are rotated. There is also the push button radio type, which is the current favorite since they work well and last a long time. The drawback is that they are very expensive and hard to get (special order). We're thinking of about 4 cabs, with at least a couple of dozen blocks, so minimizing part count is important. Any ideas? Tony Burzio San Diego, CA [ August 02, 2005, 02:43 PM: Message edited by: Tony Burzio ]
Tony, I agree with the problem with rotary switches. I tried a momentary disconnect (a normally-closed pushbutton) on Cab 2, so I could go from Cab 1 to Cab 3 without the surge. It worked but, unless you were very dextrous, took two hands to throw. Cab 1 to Cab 4 would take two pushbuttons, for Cab 2 and 3. I'm not familiar with the pushbutton radio type switches. Most rotaries are double-pole. Just before I went to DCC, I thought about connecting Cabs 1 & 3 to one pole, and Cabs 2 & 4 to the other. I didn't get very far, because I'm not very logical. With complicatd track--and I assume a club wants complicated track, if only to show off--the problem gets hideous. I had some complicated track on my previous layout, and had control switches that should have had these instructions on the fascia: When operating east in forward, throw this switch to east. If operating east in reverse, throw this switch to west. If operating west in forward, throw this switch to west... It would seem, logic aside, that each block would have to be isolated on both sides, hot and ground. That's just good practice in any case. (Lost rest of post when keyboard malfunctioned.) Grr! Later!
What about installing a normally-closed momentary push button in series with the rotary switch? It would cut power to the rotary switch while the button is pressed. When you want to select a different cab, you push and hold the button while you select the cab with the rotary knob. That would eliminate the annoyance of momentarily powering the other blocks like you mentioned above but still using cheap components. On the other hand, it has the down side of requiring two hands to operate.
That's a good idea, but it drives up the part count. The radio button is about a dollar more expensive than just a rotary alone, and it by definition can't have two inputs connected at once. Once you add the push button, the radio buttons win on a TKO. Hmmm... Is there a rotary switch that you have to push in first to turn, which also breaks the contacts?
They make that kind of switch for washing machines that I know of, but whether you'd be able to find that sort of thing off the shelf for what you want at a reasonable price...???? I use something like what Pete was describing; my power comes into six position rotary switches and from there to DPDT center off switches mounted on my track diagram. I use the DPDT switches to set the direction exclusively, i.e. if I want the train to go to the left, I push the switch to the left and so on. When I want to cut power to a section of track, I set that section to the center (off) position. I don't claim that it's the easiest way to do it, but it seemed like a good idea at the time, considering the parts I was able to find off the shelf.
Yes, it'll have that too. Meanwhile, the 1000 locomotives that myself and my friends have will take a while to get converted... Tony Burzio San Diego, CA
I've operated on some large HO layouts with rotary switch controls. Have done both engineer, and dispatcher positions. Power at the individual tracks was contolled by SPST switches. The rotary switch was used to assign a throttle to that block. There was no lag or surge, as you did it ahead of the moving train. Boxcab E50
Could you expand on this? Was there one rotary which powered multiple blocks, with on/off SPST switches to disconnect secondary blocks like sidings, or was the SPST to stop power to the block while a new throttle was selected on the rotary to stop surges? I also heard of a method that uses a bank of DPDT toggle switches. The first one from the left that is up gets the power. Simple daisy chain, but it's users (San Diego Model Railroad club) didn't like it in practice and went to radio push buttons.
