Model Railroading > Phone System

Has any one put a phone system in for their layout. We have been using radios when we operate but I thought a phone system might be nicer. What did you use?

It may be simpler for each operator to bring their cell phones if they have them since they are small and fit into your pocket. Also you may obtain a few on sale to use on your layout, the very basic ones should not cost very much. I happen to use Cobra walkee - talkees in my RV and since they are very small they would be ideal for a layout.

Hal

I use a phone system for my layout, I model Conrails Indy line. The phones I have are from a friend of mine that works for CN. Indy yard,Marion yard,and Cleveland colling wood yard have a phone. The yard masters contact our Terminal dispatchers office. Train crews contact the terminal for permission in and out of the yard. Yard masters call terminal for trains that are built, and what trains have switching moves while in route.

Conrail1
Chuck

I've been aquiring from eBay old phones to eventually use. I like the heft. Makes tings seem a bit omore real.

What equipment are you using to connect the phones together

I've been considering the idea as well. Do you use
coax cable around the layout and plug the phones into
jacks, or are they hard wired permanently?

I presume you could hook the phones together with a bunch of multipole relays and a simple amplifier?

Actually I haven't got that far. I've got a coulple of old phones and will have a friend who knows all about such Black Arts set things up.

You oughta see if you can get some old military sound powered phones. The Navy around the neck version would be great for a dispatcher or tower operator and the field phone version for various stations. Not usre how many stations you would need before an amplifier is needed. Half a dozen should be no problem.

Back when I was a young buck I was an IC electrician in the Navy, which means I was the guy who maintained the sound powered phone systems, among other things. A very simple and robust system BTW. We had many circuits, some of which ran the entire length of the ship (350 foot or so and 4-5 decks vertically). You could have 8-10 phones on a circuit before you needed amplifiers. Voltage loss due to transmission length wasn't as much of an issue, although I suppose this could be different on something large like an aircraft carrier. These are 25 year memories here, so bear with me :)

A side note here, one of the things I really enjoy about the new Battlestar Gallactica is the way they use USN standard IC gear onboard. The handsets they talk into look like radio handsets, and the radio they listen to (the gray box with the buttons and round circular speaker) is a standard USN bitch box intercom. (Fixed those too :)) I caught them using SP phones once during an attack too.

SP phones work by converting the mechanical energy of speech (moving air) into electrical signals through magnetic induction. Pretty much like any other microphone. A coil on the moving tympani moved inside the permanent magnetic field generated a electrical waveform, that would go down the wire to the other end, where it would excite another magnetic field, causing the earpiece tympani to move, resulting in moving air that the guy on the other end heard as speech. The mouthpiece had a rubber cup that trapped the speech and the earphones were very cushiony, blocking out the background noise. There were SP handsets too. To prevent noise on the line you had to press a button while speaking into the phone. If the button switch wasn't closed then the microphone wasn't connected to the circuit.

Key to this is clean connections and low resistance wiring. I'd say it was 18 ga stranded twisted pair, with crimp terminal plugs. These are very low voltage and amperage signals. If there is any resistance or ground faulting along the way the signal will be lost. SP trouble reports always came down to a loose connection in a junction box (lots of vibration on board) or rarely a damaged cable due to some numnutz.

If you can get enough SP phone sets they should meet your needs. Wiring is simple - two wire plus and minus. Connect all phones the same way (white to white, black to black, plus to plus, you get the idea) and you should be good to go. Remember quality electrical connections are mandatory.

Good luck,
Clarence