Signals
Planning a Test Track
20 May 2017 00:31
I’ve been thinking about this for about two years now, but it’s finally made it to the head of my “things to do” list: I want to build a short test track using the techniques I plan to use for the new layout: code 55 flex track and turnouts made using the Fast Tracks soldering jigs.
There are several reasons for this: first, I want to refresh my flex-track skills. Second, I want to learn how to use the jigs to make turnouts. Third, I want a fairly complex interlocking where I can try out electronics for detecting trains and controlling signals and interlocking those with turnouts, as well as interfacing all of that to DCC and JMRI running on a computer. And finally, I need to test some trains and see if they have any issues with this type of track.
So the first order of business was to figure out what I want the interlocking to look like. I started by sketching out an interlocking with a couple of tracks and some sidings, which was a nice, generic, interlocking, but not really representative of what I want to model. I’m modeling high-density urban commuter passenger lines in Tōkyō, and those are double-track with few sidings.
So that turned my thoughts to the junction between the Chūō Line and Sōbu Line at Ochanomizu Station, and the set of interlockings just to the west of there, between Ochanomizu and Suidōbashi stations. I’ve done a lot of research on that area, and know the layout of the track and associated signals fairly well. It has a mix of 3, 4 and 5-lamp signal heads, so I can test most and maybe all of the signal types I’d use. Plus it’s a very complex environment, which makes for a good test.
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There are several reasons for this: first, I want to refresh my flex-track skills. Second, I want to learn how to use the jigs to make turnouts. Third, I want a fairly complex interlocking where I can try out electronics for detecting trains and controlling signals and interlocking those with turnouts, as well as interfacing all of that to DCC and JMRI running on a computer. And finally, I need to test some trains and see if they have any issues with this type of track.
So the first order of business was to figure out what I want the interlocking to look like. I started by sketching out an interlocking with a couple of tracks and some sidings, which was a nice, generic, interlocking, but not really representative of what I want to model. I’m modeling high-density urban commuter passenger lines in Tōkyō, and those are double-track with few sidings.
So that turned my thoughts to the junction between the Chūō Line and Sōbu Line at Ochanomizu Station, and the set of interlockings just to the west of there, between Ochanomizu and Suidōbashi stations. I’ve done a lot of research on that area, and know the layout of the track and associated signals fairly well. It has a mix of 3, 4 and 5-lamp signal heads, so I can test most and maybe all of the signal types I’d use. Plus it’s a very complex environment, which makes for a good test.
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Ochanomizu Station Signals
03 April 2016 23:28
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
15 March 2016 23:24
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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Scene Planning - Chūō Along the Kanda
15 February 2016 22:51
My next layout is still very much in the back-of-a-napkin planning stage. I’m thinking about what goes into it more than the details of how I realize that. I have several things I know I want: multi-track urban commuter railroading, “layered” scenery with water, roads and railroads crossing each other at different levels, and prototype scenes from the core of Tōkyō. But just exactly what that means hasn’t fully come together yet.
One thing I do know that I want is a riverside scene or scenes along the Kanda river. This is a small river, running east to west and ending at its intersection with the much larger Sumida river in the center of the city. Near the eastern end it passes just south of the famous Akihabara district. A four-track mainline runs west along its south bank for a mile or so (about 2 km) before turning southwest along a different waterway and ultimately disappearing into a tunnel and turning north into Shinjuku station.
The railway along these two waterways lies in the center of Tōkyō, between the eastern and wester sides of the Yamanote line loop, which passes through Tōkyō station on the eastern end and Shinjuku station on the western end, and it serves as a shortcut across the middle of that line. Originally this was part of the Kōbu Railway, built in the late 1890’s, although portions were completed shortly after nationalization of the railways occurred in 1906. This can be seen in the largely wooden construction of the stations, with complex riveted girderwork in places.
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One thing I do know that I want is a riverside scene or scenes along the Kanda river. This is a small river, running east to west and ending at its intersection with the much larger Sumida river in the center of the city. Near the eastern end it passes just south of the famous Akihabara district. A four-track mainline runs west along its south bank for a mile or so (about 2 km) before turning southwest along a different waterway and ultimately disappearing into a tunnel and turning north into Shinjuku station.
The railway along these two waterways lies in the center of Tōkyō, between the eastern and wester sides of the Yamanote line loop, which passes through Tōkyō station on the eastern end and Shinjuku station on the western end, and it serves as a shortcut across the middle of that line. Originally this was part of the Kōbu Railway, built in the late 1890’s, although portions were completed shortly after nationalization of the railways occurred in 1906. This can be seen in the largely wooden construction of the stations, with complex riveted girderwork in places.
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LCC, For Real
31 January 2016 01:55
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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Signals II: Block Systems
06 September 2015 00:38
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
11 August 2015 22:46
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.
Read More...
