Signals
Ochanomizu Station Signals
JR’s Ochanomizu Station (御茶ノ水駅, Ochanomizu-eki) is an important part of my modeling plans. As seen in the photo above, it’s a mix of old and new architecture. And it’s built along the bank of the Kanda river (the temporary construction platform on the right is actually erected over the river). It’s slightly below street level, with a city skyline climbing up behind it from a front rank of buildings around six stories in height to taller ones further away. It’s pretty much ideal as a modeling subject visually, and it sits at the junction of two busy lines, so there is a lot of activity.
I have been trying to figure out how the signals here and nearby work so that I can include a reasonable subset in my model, but photos in and around the station tend to focus on other subjects than signals for some reason. Thanks to one of my readers, George Roberts, I now have a number of photographs taken around the station and adjacent areas that include these signals (and other interesting details).
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I have been trying to figure out how the signals here and nearby work so that I can include a reasonable subset in my model, but photos in and around the station tend to focus on other subjects than signals for some reason. Thanks to one of my readers, George Roberts, I now have a number of photographs taken around the station and adjacent areas that include these signals (and other interesting details).
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Modeling Prototype Signaling I
Today's post follows my earlier series on prototype signaling (Part I: Development and Part II: Blocks), but it's about how to capture a specific prototype environment on a model railroad. For example purposes, I'm going to look at a real-world location I plan to model, Ochanomizu station and the crossovers just west of it. This is a fairly complex case, as it involves a junction of two double-track lines. On the other hand, it's a relatively simple station without multiple platforms per track, which simplifies things a bit.
The question at hand is: how would I replicate somewhat realistic prototype signals for this location? It's an important question, as I'll eventually need to do it. And determining the right answer is a good way to clarify my understanding of the topic, so I can create similar solutions for other locations on the layout. I may or may not actually do it this way when the time comes, but working through this example now helps clarify my thinking.
But I’ll get into the detail of that in another post. For now I’m going to focus on the signals and related systems around a simple crossover (above) so that I can introduce the various pieces that make up the whole, and explain how they fit together.
I started by studying everything I could find about the real signals at this location, which I wrote up as part of my post about this line. Mostly that involved looking at photographs, although before that I'd studied the MLIT document (PDF) that defines how Japanese railroads are supposed to use signals, as well as checking Wikipedia and other sources. I cover all of that in my prototype Signals pages.
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The question at hand is: how would I replicate somewhat realistic prototype signals for this location? It's an important question, as I'll eventually need to do it. And determining the right answer is a good way to clarify my understanding of the topic, so I can create similar solutions for other locations on the layout. I may or may not actually do it this way when the time comes, but working through this example now helps clarify my thinking.
But I’ll get into the detail of that in another post. For now I’m going to focus on the signals and related systems around a simple crossover (above) so that I can introduce the various pieces that make up the whole, and explain how they fit together.
I started by studying everything I could find about the real signals at this location, which I wrote up as part of my post about this line. Mostly that involved looking at photographs, although before that I'd studied the MLIT document (PDF) that defines how Japanese railroads are supposed to use signals, as well as checking Wikipedia and other sources. I cover all of that in my prototype Signals pages.
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LCC, For Real
Well, it didn’t take long. The first useful commercial products based on the LCC standards are out, and I have a set. While I may have some reservations about the state of the standards themselves (see my earlier series of posts), I’m very excited to see real products, and at fairly reasonable prices. Well, somewhat reasonable; I’ll have some comments on that.
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New Plans for a New Year
I'm going to usher in the new year with a new project, and try to get back to doing more frequent but smaller posts than I've done of late. I'm not quite back to railroading yet, although this is ultimately in support of that. But for the moment, I'm still playing with microelectronics. And today's post is just a summary of where I'm going and what I've done so far, which doesn't amount to much when you put it down in words.
I'm still thinking about and planning the next layout. Control systems are a big part of that, because I was never happy with the DCC-throttle control of turnouts I used on Sumida Crossing, and my attempt at a single big computer-driven system never got off the ground, and would have had some of the same issues if it did.
As you may have noticed, I've spent a lot of time looking at control bus systems over the last two years. I'm still on the fence about what to use, as I don't particularly like any of the current systems. LCC has promise, but so far that's all it has, and I'm not expecting much from it in the next couple of years; it's too new.
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I'm still thinking about and planning the next layout. Control systems are a big part of that, because I was never happy with the DCC-throttle control of turnouts I used on Sumida Crossing, and my attempt at a single big computer-driven system never got off the ground, and would have had some of the same issues if it did.
As you may have noticed, I've spent a lot of time looking at control bus systems over the last two years. I'm still on the fence about what to use, as I don't particularly like any of the current systems. LCC has promise, but so far that's all it has, and I'm not expecting much from it in the next couple of years; it's too new.
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Signals II: Block Systems
On a railroad, lineside signals provide information to the person driving a train (the driver or engineer, depending on which country you live in; I’m going to use the word “operator”). This allows them to go faster than if they were limited to what could be seen directly. Trains are heavy and steel wheels on steel rail slide fairly easily, so it can take more than a mile (1.6 km) to stop a train moving at a reasonable speed.
Braking distance isn’t the only thing that affects train speed. At places where tracks diverge, or when changing tracks, a train may need to slow down due to the speed limit imposed by the turnout(s) being used. For this reason, signals used at places like this (one of several types of “interlockings”) get more complicated. As noted above, I’ll address that aspect in a future post.
Where trains don’t have a choice of direction, what controls speed are two things: unchanging limits imposed by equipment or track, and variable limits due to conditions ahead. Inherent limits are things the operator knows before boarding the train: the limits of the equipment and permanent speed limits imposed by track geometry (sharp turns, etc), and temporary limits (such as a limit imposed until a known problem can be fixed). Those limits may also be posted on signs, although this depends on the railway, and often the operator is required to memorize both the normal limits and any special limits in effect that day.
Block signals historically have worked to limit speed based solely on knowing how many block sections ahead of the train are clear, up to some maximum. The speed limit associated with a given indication is either encoded into the interpretation of the signal (e.g., “yellow means 30 mph”) or another detail the operator needs to memorize. The signals work by using electrical “track circuits”, which can also detect rails that break due to accident or environmental conditions (rails stretch and shrink as temperature changes, and sometimes they snap).
This makes block signals, usually, much simpler than interlocking signals. However, block signals adjacent to an interlocking may be a hybrid of the two, and able to display additional information relevant to the interlocking while still being part of the block. We’ll cover that aspect with interlockings, and today focus only on block signals away from interlockings. These are sometimes called “intermediate block signals”.
Fundamentally block signals provide an indication of the distance (in block sections) a train has before it must come to a halt. That can be “unlimited” (meaning longer than the worst-case braking distance) or some number of blocks. It’s not that simple of course.
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Braking distance isn’t the only thing that affects train speed. At places where tracks diverge, or when changing tracks, a train may need to slow down due to the speed limit imposed by the turnout(s) being used. For this reason, signals used at places like this (one of several types of “interlockings”) get more complicated. As noted above, I’ll address that aspect in a future post.
Where trains don’t have a choice of direction, what controls speed are two things: unchanging limits imposed by equipment or track, and variable limits due to conditions ahead. Inherent limits are things the operator knows before boarding the train: the limits of the equipment and permanent speed limits imposed by track geometry (sharp turns, etc), and temporary limits (such as a limit imposed until a known problem can be fixed). Those limits may also be posted on signs, although this depends on the railway, and often the operator is required to memorize both the normal limits and any special limits in effect that day.
Block signals historically have worked to limit speed based solely on knowing how many block sections ahead of the train are clear, up to some maximum. The speed limit associated with a given indication is either encoded into the interpretation of the signal (e.g., “yellow means 30 mph”) or another detail the operator needs to memorize. The signals work by using electrical “track circuits”, which can also detect rails that break due to accident or environmental conditions (rails stretch and shrink as temperature changes, and sometimes they snap).
This makes block signals, usually, much simpler than interlocking signals. However, block signals adjacent to an interlocking may be a hybrid of the two, and able to display additional information relevant to the interlocking while still being part of the block. We’ll cover that aspect with interlockings, and today focus only on block signals away from interlockings. These are sometimes called “intermediate block signals”.
Fundamentally block signals provide an indication of the distance (in block sections) a train has before it must come to a halt. That can be “unlimited” (meaning longer than the worst-case braking distance) or some number of blocks. It’s not that simple of course.
Read More...
Signals I: Development, Regulation and Use
For more than 150 years, signals beside the tracks have been used to provide guidance to the operators of trains. Originally this was a simple “stop” or “go” message, but over time it became more elaborate, and the signals themselves more complex. Today signals provide fairly detailed guidance that allows for efficient and safe operation. But how they do that varies a lot between railroads. Signals have also become specialized, with signals at stations, junctions and similar points (“interlocking signals”) behaving somewhat differently from signals along uninterrupted lengths of track that exist mainly to separate trains (“block signals”). There are also many other, more specialized, signals.
Signals used in Japan are both simpler than those used in many other places, and allow for some capabilities that others do not (or that they do using more complex methods). But they also have a lot in common with signals used elsewhere. That shouldn’t be a surprise, as Japanese practice originated, as did that of many other countries, in British practice of the late nineteenth and early twentieth centuries. However they were also influenced by North American practice (which itself originated from mid-to-late-nineteenth century British practice). And they created some things unique to themselves. But I think that to understand them, it helps to take a look at how signals are used on railways around the globe, particularly block signals, as Japan has streamlined their system by focusing on block functions.
I’m going to leave Japan for this post and wander the globe for a bit before I get back to explaining Japanese signals in a separate post. But I will include Japan in today’s discussion.
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Signals used in Japan are both simpler than those used in many other places, and allow for some capabilities that others do not (or that they do using more complex methods). But they also have a lot in common with signals used elsewhere. That shouldn’t be a surprise, as Japanese practice originated, as did that of many other countries, in British practice of the late nineteenth and early twentieth centuries. However they were also influenced by North American practice (which itself originated from mid-to-late-nineteenth century British practice). And they created some things unique to themselves. But I think that to understand them, it helps to take a look at how signals are used on railways around the globe, particularly block signals, as Japan has streamlined their system by focusing on block functions.
I’m going to leave Japan for this post and wander the globe for a bit before I get back to explaining Japanese signals in a separate post. But I will include Japan in today’s discussion.
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Signals and Signaling with Arduino
I’m going to vary from my normal focus on modeling Japanese railroads today to talk about signals and modeling them in a more general sense. Heck, who am I kidding, there haven’t been many posts on modeling Japanese railroads of late. But I digress from my digression. Back to the subject: signals.
If you want to cut to the chase: I’ve written an Arduino library for controlling lineside LED-based signals. It’s only part of a complete signaling system that I’m working on, and at present you’d have to do more work to make practical use of it. But the code is public and can be used independently of anything else I’m eventually going to create; skip down to the end for details.
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If you want to cut to the chase: I’ve written an Arduino library for controlling lineside LED-based signals. It’s only part of a complete signaling system that I’m working on, and at present you’d have to do more work to make practical use of it. But the code is public and can be used independently of anything else I’m eventually going to create; skip down to the end for details.
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Arduino Signals II - Video and Flickering
I’ve continued working on the code to drive LED signals with an Arduino. I’d previously discussed my approach, and provided the code I was using at that time. I’ve learned a bit since then, and cleaned up the code significantly. I’ll provide a link to the current example program at the end of this post.
Fundamentally nothing has changed. I’m still planning to use NJI common-anode SMD LED signals (in fact, I’ve ordered them). What I did do was change the code so that a “bank” of two signals would always have both lit (meaning two of the four LEDs would be on when the bank was active) so that I could get through the full set of signals more quickly. One reason for this has to do with video camera shutter speeds. I think it’s worth saying a bit about that issue.
I’ve also made some changes to make the time wasted in turning the pins on and off less, since at these speeds that is becoming a significant percentage of the total LED cycle, and I need that time for the eventual Tram Controller program to be doing other things. These changes consisted of adding a library that provides faster versions of writeDigital and pinMode, as well as keeping track of what state pins are on, and not trying to change them unless the new state differs (this got rid of a number of “change disabled pin X to disabled” changes).
In my test program, when cycling at 8 milliseconds, I’m now spending just a quarter millisecond changing those pins with three banks (6 signals) in use. My One Point Five Meter line will only use four signals, as it doesn’t have the extended double-track section of the full Tram Line, which needs six. And so it will run even more efficiently. Read More...
Fundamentally nothing has changed. I’m still planning to use NJI common-anode SMD LED signals (in fact, I’ve ordered them). What I did do was change the code so that a “bank” of two signals would always have both lit (meaning two of the four LEDs would be on when the bank was active) so that I could get through the full set of signals more quickly. One reason for this has to do with video camera shutter speeds. I think it’s worth saying a bit about that issue.
I’ve also made some changes to make the time wasted in turning the pins on and off less, since at these speeds that is becoming a significant percentage of the total LED cycle, and I need that time for the eventual Tram Controller program to be doing other things. These changes consisted of adding a library that provides faster versions of writeDigital and pinMode, as well as keeping track of what state pins are on, and not trying to change them unless the new state differs (this got rid of a number of “change disabled pin X to disabled” changes).
In my test program, when cycling at 8 milliseconds, I’m now spending just a quarter millisecond changing those pins with three banks (6 signals) in use. My One Point Five Meter line will only use four signals, as it doesn’t have the extended double-track section of the full Tram Line, which needs six. And so it will run even more efficiently. Read More...
Signaling with Arduino
t seems that I can never resist the impulse to make things more complicated. While working on my Arduino sketch (program) for the Tram Controller, the thought struck me that I could add signals at the stations to tell the fictive operators of the trams when it was safe to leave. These would be “starting signals” in typical Japanese practice, and only require two LEDs, red and green. Of course I’m all out of pins, and the only step up from the Uno, which has 20 pins (14 digital, 6 analog) is the Mega with a whopping 70 pins (54 digital, 16 analog).
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Computer Support
A computer is part of my model railroad. Why, and how do I use it? Well, the answer to the last question is “not very much”, so far, but I have plans. I recently had to re-do the monitor support attached to the layout, and I thought I’d discuss the reason it’s there, as well as the work on the support itself.
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NMRAnet - Why You Should Care
In August, the NMRA adopted standard S-9.7.1, NMRAnet Physical Layer, and a short article about it appears in the November issue of the member's magazine. What is this, and why should you care about it?
Well, if you care about Digital Command Control (DCC) for controlling a model railroad, it's an important addition to model railroading that will enhance that. And if you don't care about DCC, it's compatible with other control systems, and you may still want to use it. Read More...
Well, if you care about Digital Command Control (DCC) for controlling a model railroad, it's an important addition to model railroading that will enhance that. And if you don't care about DCC, it's compatible with other control systems, and you may still want to use it. Read More...
DC Signals I: Kato
27 June 2011 22:22 Filed in: Electrical,DC
This is the first of what will probably be two postings about simple trackside signals for DC layouts. This one will discuss the basics common to the Kato and Tomix signal systems, and then provide details about Kato. Since I’m partly looking at the Kato to see if it’s a good candidate for modification for my DCC layout, I’ll have a few comments on that as well. A future posting will cover Tomix’s richer offering, which I’m looking at for use on my DC Urban Tram Layout (which will probably use the Tomix signals), although the four-color signal heads might be something I could use for my DCC layout (nobody in the U.S. makes a four-lamp signal of this kind).
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Kato Modular Buildings
21 May 2010 19:43 Filed in: Structures,Electronics
Today I’ll turn my attention to what goes atop the scenery: buildings. There’s going to be much more on this, and I’ve created a Structures section of the website with its own index page to contain such material, but so far it’s pretty vacant. Today’s post introduces the first page there, describing Kato’s modular multi-story buildings.
Kato makes several modern six-story buildings that are generic enough to use in any city, although they also include signs to decorate them for a Japanese one. But what really makes these buildings special is that they’re modular, and while Kato doesn’t sell the floor units separately, you can combine two or more buildings to make some reasonably tall structures. Read More...
Kato makes several modern six-story buildings that are generic enough to use in any city, although they also include signs to decorate them for a Japanese one. But what really makes these buildings special is that they’re modular, and while Kato doesn’t sell the floor units separately, you can combine two or more buildings to make some reasonably tall structures. Read More...
