All three tracks would be

All three tracks would be protected. There are exceptions covered under local operating rules, but model railroads are more plausible when the "typical" is followed.

Any place a track crosses a

Any place a track crosses a road it should have some sort of protection,  aka sign. 

Section of unused track that is connected to nothing out here still gets new signs as if it is in use.  Seems odd,  but the the DOT rules say something about it being a track over a road,  it gets sign.  

Why?  Just in case UP puts that track back in service all those crossing are covered with minimum protection aka a sign

Protection

Thanks for the replies.... sorry I wasn't more clear in my explanation my fault... I realize that all three tracks must be protected in some manner but what I was trying to ask was would a lighted crossing signal be used for only the mainline and the sidings would be protected by the crossing signs that are already installed?

All 3

All three would be included in the circuit and all three would be between the signals.   The masts would have a sign that reads "3 TRACKS".

The circuits will not be the same on all three tracks, the main approach circuits will go out a half mile or more, the industry track circuits may only go out a car length on either side or might not have an approach circuit at all, they might be activated by the crew.

Unless you have different railroads or their is enough space for a truck  to safely be between the tracks and clear all the tracks, they would not have separate signage.

"All three would be included

"All three would be included in the circuit and all three would be between the signals. The masts would have a sign that reads "3 TRACKS"." Not correct. C'mon, Dave, you of all people know there are always exceptions. I work around at least on location where a spur is protected by local operating rules, while the two main tracks 25 feet away are protected by flashers and gates.

And not all three tracks, even with gate/flasher protection for all three, would be "in the same circuit." The main tracks would be on a predictor; the spurs on anything ranging from a predictor to a motion detector to a AC battery/relay circuit to DC track circuit, or even just a switch circuit controller breaking an input into the main track bungalow's crossing relay chain.

Circuit

I'm pretty sure he means that the circuit(s) on all three tracks will in some way be able to trigger the crossing circuit - there's only one set of flashers. So there's still a single circuit that is tripped.

Good info

Thanks for the great info... I had assumed what you are all saying that the signal would be for all three tracks. But not working in the railroad industry myself I just wanted to make sure what would be prototypical and I was unable to find anything on DuckDuckGo.

Layout

Cool.  His tracks aren't 25 ft apart.  They are on what looks like 15 ft track centers.  There really isn't even enough room to put a sign post between the tracks and maintain clearances.

"Thanks for the great info...

"Thanks for the great info... I had assumed what you are all saying that the signal would be for all three tracks. But not working in the railroad industry myself I just wanted to make sure what would be prototypical and I was unable to find anything on DuckDuckGo." In this case, the flasher/gates would protect all three tracks. Just be wary when anyone says the prototype would "always" do something a certain way. Almost always an exception can be found, and signaling is no different. Heck, I've even seen a three-aspect dwarf signal with the red aspect on top, green at the bottom due to restricted visibility. Seeing the red is more important. Thankfully it's a lot easier to get info these days.

.

No one has used the word "always" at any point previous in this thread.

You can do that?

LOL....!!!

Agree with all your statements... maybe I should have just said what would be more common?

I remember and old physics professor said in class once, "their are no absolutes, the only absolute is that you can never say never even though I just said you never can say never.".....   LOL.... guy was absolutely hilarious...

"No one has used the word

"No one has used the word "always" at any point previous in this thread." Oh, my apologies. Do you know something more about the specific topic and wish to add something? I can't see how advising the OP to be aware of "always" statememts when it comes to the prototype would be in the least disconcerting to anyone.

Main only

The cross bucks/flashers/gate would protect all three tracks. However, It's just as likely only the main has the island circuit. While the spurs have interlocks with the switches/details.

I worked several locations where the protection activated when I dropped the derail into an industry. There was also one location where I had to manually active the protection. 

Nick

Awesome Nick.... logically that's what had assumed how things would work. I appreciate the input. My plan is to put a button on the fascia to activate the signal. 

Nick when you say you had to manually activate the protection how is that done? Do you have to go to one of those for signal "huts" and activate it there? Or what other ways does a signal get "manually" enabled and disabled? 

Manual

It could be a switch connected to the switch or derail.  A little metal box, about 18" x 12" x 12" bolted to the tie connected by a rod to the derail or switch.

Or it could be a box about the same size bolted to the crossing signal mast that the crew unlocks with a switch key and the switch is inside the box. 

Or there could be a signal cabinet next to the crossing and there is a door in the cabinet  with the switch behind it.

The Hut

Ben,

The signal bungalow had box on the outside, secured with a switch lock, containing a switch. IIRC it was actually two push buttons. One for on and one for off.

how do you know

With all the variety of places the switch could be and ways to activate it, and the possibility that it's automatic and there is no manual switch, how do you know what you have to do if you don't already know?

Are you sure you need crossing signals?

I recall many industrial areas that just had crossbucks with an attached  sign telling the number of tracks. There was even one crossing Watsonville yard that said something like 11 tracks :> )  Crossing there was kinda like playing frogger....DaveB

Where’s the switch

Special instructions in the timetable or general orders, notices or bulletins.