BNSF Signal

I want to include an operational signal on my module to protect a spur track from the mainline. I am modeling BNSF in 2001, so I was hoping to use a Santa Fe searchlight signal. Here is a picture of the mainline portion of the track plan. The train will back in to drop off cars. How would the signal work? Would it be red when the switch is turned and green when open? Is there more than those two colors? Would a second signal head be used?
The arrows show the direction of travel for each track. My thought was that the signal would stop a train on the mainline from hitting another train backing in to drop off cars.

 

The signal should be on the field side of the spur track protecting the main. It would govern movements onto the main from the spur track. There should also be a derail located near the signal.

This signal and switch would be located in a signaled block with signals on either end (although they don't have to be modeled if they are past the limits of the layout or module). This would be a non-controlled absolute signal and it would display red if the switch was lined for the main and yellow if the switch was lined for the spur track. The exception would be if equipment was left on the main while the switch was open then the signal would display red, or if another train was still in the block after authority was granted to enter the main.

This signal would not grant authority to occupy the main track; that comes from a dispatcher. An example of the authority might be, "BNSF 1234 (train id) at Willbanks (industry/signal location), you have authority to enter main track between CP 123 and CP 131 for a northbound (direction) move, over." If it's after a certain train passes by, you might have to indicate "CP 2345 North (train id) is all by your point of entry" before being granted the authority.

 

So you're saying that the signal would be on the spur to stop trains going on the main, and a dispatcher controlled signal, possibly miles away, would stop a train on the main from hitting a train stopped to back into the spur? I had always assumed the signal would be on the main, but your description makes more sense. The mainline should have athority over a train on a diverging route. I drew a quick diagram of what I think you said.

 

Yes, that looks right. Blocks are typically about two miles in length, but they can be much longer or as short as a few hundred feet.

It's difficult to go into too much detail without knowledge of the various types of signal and operation combinations you could have based on your example, so I'm responding as if your example shows two main tracks with CTC. Two Main Tracks means trains can be authorized to use either track in either direction. This contrasts with Double Track, which means trains can be authorized to use either track with the current of traffic.

Trains could also be granted authority by a track warrant and the signals could be ABS or Automatic Block Signals. In ABS, the signals don't give you authority to use the main; they simply convey information about the block and the blocks ahead. In other words, a green signal in ABS tells you the block ahead and the block after that is clear and the next signal could be yellow but not red. A yellow signal tells you the block ahead is clear and the next signal could be red. Neither yellow or green ABS signals by themselves allow you to proceed; that authority must come from the dispatcher. Only with authority may you proceed. The signal just tells you how you are going to proceed (at track speed, prepared to stop short of a red signal, at restricted speed, and so on).

In CTC the signal actually does give you authority to proceed and it tells you how to proceed. Green means you can proceed and the block ahead and at least the block after that are clear. Yellow means the block ahead is clear and you can proceed no more than 30 mph and you must be prepared to stop at the next signal. Red means you cannot proceed unless the dispatcher instructs you past the signal.

Bear in mind this explanation is greatly simplified and I have not described all the signals you can possibly get. If you're up for it, search for GCOR and look over chapter 9, specifically 9.10 and 9.17, and 10.1 and 10.2 in chapter 10. You will also learn a lot just by going through the glossary. In all likelihood you will have more questions than answers, but if you do that's a good thing. That knowledge will open up a whole new level of enjoyment in your operating and railfanning.

 

This is true. The size/height of the signal may vary by location, railroad or some other factor such as an obstruction. Here is an example on the UP (former FW&D) just north of Fort Worth, Texas:



You can see the two-aspect signal (it only displays yellow or red) as well as the derail sign and flop derail over the top of the near rail. The main track passes between the curved spur track in the foreground and the dumpsters behind it. If your train is in the clear of the main on this industry track and the switch is lined and locked for the main, you will need dispatcher's authority before opening the switch. When you have the authority and you've lined the switch and the block you will enter is clear, the signal will change to yellow.

 

For that spur there would be signals on both sides of it on the mainline. Also there would be a signal for the spur itself as shown in your 2nd image. The signal in "front" of the spur would be 2 headed to tell the engineer/conductor which way the switch is lined. the signal behind the spur would be single head as it only tells the crew to proceed or stop. Same thing for spur signal. Find "GCOR" thru Google to read about RR signals. Also see if you can find an employees timetable for the area you're modeling to see all the rules for signals. Also is this spur a specific prototype or a freelance creation? Back in 2001 not all spurs had signals, but the train still needed dispatcher's authority to work it if it was in signaled territory.

 

What you are describing is a control point. In CTC territory, a control point is a point where the dispatcher has control of the signals. It can also be an area containing one or more switches with signals facing away from and along each route from the switch(es).

A control point with one or more dual control switches (a power operated switch that can also be operated by hand) has signals beyond the clearance point of the main and siding, spur or other track on the trailing point side of the switch and before the switch points on the facing point side of the switch. The dispatcher has control up to a point - you can't make a signal display clear if there's a train in the next block, for example - but he or she can give the intent for the signal system to authorize a certain move if the conditions allow.

That's not necessarily true. It depends on the track layout and signal configuration ahead. If the next signal is a control point with two or more routes that can be taken, there will likely be signals that can convey this information at the previous control point. For example, if you will be crossing over from main one to main two at the next control point and the tracks ahead are clear, you will see a yellow over yellow at the first signal and a red over green at the crossover signal.

The GCOR itself won't be much help since the signals are described in a supplement document. Moreover, GCOR doesn't go into much detail on anything besides stop, stop and proceed and restricting. I'll attach the current signal document if I am able.

This is an excellent point, because system-wide signal rules may be modified locally. When I worked out of Tulsa I was surprised to learn a yellow over yellow signal was called "approach diverging" like on the UP but that the rule was still the same as BNSF's "approach medium," which is the name on BNSF for both double yellow and flashing yellow. Flashing yellow on UP is called "advance approach" and of course BNSF has one called by that name, too. Is your head spinning yet?

Most spurs are not signaled to this day. It's common practice to use an electric time lock on switches that are connected to the main or other controlled track, especially if the track speed is higher than 20 mph. In the scenario you described where each route is signaled at a CTC control point, the signal displaying a proceed indication is your authority to enter the signaled block and occupy the controlled track.

 

This is a ton of information, and I have no idea how you guys can just remember all of it. I'll have to do some serious studying of the BNSF signal system, and I still haven't fully decided on a prototype location. My club is a bit vague on the information they have given us about modules, but we are supposed to be starting the construction at the next meeting, and I hope that they tell a bit more then.

 

Trainiac
If you really want to learn signals become a conductor. But you have to pass several tests & you HAVE to know signals because conductors run the trains. The engineer just runs the locos as directed by the conductor. But you becoming a conductor is probably not practical. If your module club is going to allow signals on the modules, it would be a good idea for the member to know signals. If it's just a few of you w/ signals, it would be helpful to the train operators to have handouts showing what the different signal aspects mean: http://utu199.progressthroughunity.org/documents/Signals

 

Thanks for that link, there is something similar on the BNSF website. That is a good point, I'm not sure how many people have signals. I know I may only have one or two, and the operating system will be simple. The only power comes from the tracks, so no bus wires for signal blocks or accessories bridging more than one module.

 

There's nothing like working with signals every day to make you learn the rules. On the railroad if you run a signal it's not like on the road where you might get a ticket and go on about your business. You will be pulled from service.

I'm fortunate to work in an area made up of several predecessor railroads each with many lingering characteristics or idiosyncrasies from the original road. It's a lot to deal with, but it helps establish a good understanding of the rules.

You and your club might want to look into the system being implemented by many Free-mo organizations, MSS:

http://www.free-mo.org/node/94

www.garymgreen.com/free-mo%20signal%20article.pdf

http://modelrailroadsignalsystems.com/​

Some time ago I made up some signal scenarios to show some of the guys in my Free-mo group who didn't have railroad experience what we see and what the signals mean (for example, "Double yellow. Looks like we're taking the siding"). They may be helpful to illustrate the signal sequence you might encounter on the ATSF you're modeling. Of course you probably won't be using the Type D signals I used in my example, but the same signals can be displayed with searchlights.

The MSS some Free-mo groups have implemented is capable of displaying some of these aspects in this sequence and I know there are folks working on the logic to display even more. It's still a quasi-ABS system at heart, so it doesn't exactly mimic every situation you'd encounter in CTC territory.

 

The various methods you can use to signal your siding have been discussed above, but the choice of signal masts you will need to use depend very much on what the next signal is along the track.

As well as just displaying red for stop and green for go you will need to be able to display distant aspects for the next mast, and that is what will determine the type of signal mast you require. Take a look at this quick reference to give you a quick idea of what aspects may be required:-

http://signals.jovet.net/rules/BNSF Signal Rules.pdf

Your original post suggests a scenario where the siding just happens to be near a block boundary, and the signal mast will just be an ordinary single head block signal with a number plate that shows:-

• Restricting or stop and proceed when red because either there is a train in the block ahead or the turnout has been unlocked (so the siding can be switched).
• Approach when yellow because the next signal is red.
• Approach Medium when flashing yellow because the next signal is yellow.
• Clear when green because the next signal is green or flashing yellow.

Usually in this scenario you will have another block signal facing the other way for the benefit of trains going in the opposite direction which may have more or less heads. Since in H0 the next block signal will typically be 60' away you may not have to model it!

Suzie x