So while my unregulated phone/DSL company was waiting for the most economical time to repair their downed cable, I worked on the Bexley CTC (under control of the Train Director at Bexley Tower) design. And got far enough into it that I felt comfortable starting construction:



These interlockings are westbound-only, for the end of double track at D'Arcy Ave. and the west entrance to the yard just before the tunnel. Signals governing eastward movements through blocks 7, 9, 10 and 11 are at Bexley depot, west of the tunnel:



The easterly 'pole line' carries 3 circuits: occupancy indications for blocks 9 & 10 coming from the Bexley panel, and block 13 coming from East Bexley.

Between Bexley Enginehouse and D'Arcy Ave. there are 6 circuits: Occupancy for blocks 9, 10, 11 and 13, a circuit triggering Yellow from driver SD9e1 and a 'turnout reversed' from Bexley panel to control relay R9T1.

Let's consider D'Arcy Ave:

SD9e1 gets its Yellow input from Bexley Enginehouse. Red comes from Oc9 OR'ed with R9T1 'normal' (for eastbound moves). The diode keeps the turnout position from changing the state of Oc9 visible to other interlockings.

The top SPDT (transfer) contact on the relay does turnout position. When it's reversed, Oc11 is grounded (activated) preventing EB moves from taking the wrong track.

The second SPDT selects whether dwarf 9e2 gets + or - voltage, changing it from red to yellow.

I hope I've clarified things a bit, but I can try different words if these don't work. Once this is posted I'll get back to work on the Bexley Enginehouse interlocking and its yard exit dwarf signals.

I got the Bexley Enginehouse interlocking working this afternoon. It isn't going to be completely functional until I finish the one to the left (RR west) of it, as Enginehouse needs relay R7T2 to tell it the position of that turnout, and thus whether to display the aspect on the Middle or High head of signal 7e1:



Here's relay R7T3 and drivers SD7e1H (high head) and SD7e1M (middle) with power and a few of the external inputs wired:



The diode that's installed implements logical OR of the turnout position and block 7's occupancy (Oc7). Turnout position shouldn't affect Oc7 because other signals need it unmodified. The two in my hand will OR turnout position+Oc7 with Oc8 for SD7e1M's Red input. Oc8 isn't affected either:



This is how the interlocking left the bench, with the Red inputs for the two SDs swapped :erm: and some details of the logic driving the yard exit dwarves (7e2 and 7e3) not yet worked out:



Here's how it looks, installed and correctly wired:



I need to work out how to build 2-light dwarf signals before I do the next interlocking, which will also give my back/knees a break from crawling under the layout in the cold.

As I posted in my 'Prototypic dwarf signals in HO' thread, I fitted my NJI two-head castings with bi-polar 1.8 mm LEDs without problems. Then I found a couple of logic issues with the Bexley signal plan posted above. I have resolutions, I think, but won't post again till both ends of the tunnel are properly interlocked.

And then my order from Free State Systems arrived (many thanks to Don Valentine, who knows the owner and gave me his email). So I started building the next two signals:



[screwed by the camera orientation sensor again, sorry]

This stagger block will replace the current WB single-head block signal on my Rowley River module. It's needed as an approach signal to the D'Arcy Ave. interlocking, and I've got a scheme to display a couple of fancy aspects on it. But first I need to analyze the output of the Logic Rail Technologies 'Signal Animator' that'll still be used when traveling with the Module Group and make sure I don't let the smoke out of something.

The Eastern was upgraded from semaphores to searchlight signals in the late 1930s. But true to its roots, the B&M re-used everything they could, including many base boxes that used to house semaphore mechanisms. Sunrise Enterprises offers both single and double (seen here) HO boxes in pewter - drilling this one out to 3/32" required an extra-long drill and patience.



FSS platforms (bottom) are sized for a scale diameter mast, somewhat less than 1/16". Having made a bit of a mess fitting them to the 3/32" masts used by ORS components, this time I thought first:

1. Heat the ring portion of the platform red hot (I used my gas stove) to anneal the brass.

2. Expand the ring to 1/16" using that hole in my MicroMark punching plate. I used a round nose plier jaw as the drift.

3. Cut the outside portion of the ring with nippers.

4. Expand to 3/32" using the next bigger hole in the punch plate (in progress in the photo).

A finished part is lying in front of the punch plate - much neater than I'd achieved before.

Free State Systems

P. O. Box 1334

Hunt Valley, MD 21030-6334

freestatesystems1@comcast.net

There is no web site, no advertising (yet), he emails a price/description list of his products. What I'm using here is from '8031 ladders & platforms'. Payment is by check, USPS delivery was prompt, I have no financial interest.

Some of my recent progress lacks a pleasing sense of resolution:

I found that D'Arcy Ave. and Newburyport End of Double Track weren't using the proper logic to generate Yellow. Easy to fix but I didn't have a spot on the terminal strip so I had to run the wire direct from the relay to the 'pole line' along the layout's framing.

I found out that a 'positive logic' AND is equivalent to a 'negative logic' OR. Luckily, the 'ground is active' components I'm using look like they'll let me use Diode-Resistor Logic to generate the Yellow output from the two active heads of the Enginehouse home signal. I'll show the picture once I have it working.

The 2-light stagger block I built is now serving as the westbound distant signal for the end of double track at D'Arcy Ave. But it's using the Signal Animator which doesn't detect occupancy. Full integration is at least one more interlocking away.

I bought some of Rob Paisley's 556-based bi-polar LED driver boards:

http://home.cogeco.ca/~rpaisley4/556...ghtSignal.html

Plus: They do approach lighting, which is the way almost all B&M automatic block signals worked. Plus: They're smaller and cheaper than Circuitron's SD-3. Minus: I can't tell whether they're displaying 'yellow' or 'red' on my Oregon Rail Supply LEDs unless I'm watching as the aspect changes. I don't see a way to adjust the 'yellow' color, so I've emailed Mr. Paisley. The SD-3's yellow is screwdriver-adjustable.

And finally, I know automatic signals should have numbers - it's how crews could tell a permissive block signal from an absolute interlocking signal. But the B&M didn't settle for just a painted plate:



Model Shipways offers etched brass numbers and letters (the Eastern used a 'P' prefix) in 2 mm and 2.75 mm sizes, but their image doesn't enlarge so I'm not sure what I'd get for my ten quid.

A 'Caution-ary' Tale (as in the yellow 'Caution' aspect of RR signals):



Yellow displayed by Oregon Rail Supply's stock bi-polar LED driven by a Circuitron SD-3 and adjusted to my taste.



Yellow displayed by ORS stock LEDs driven by a non-adjustable Signal Animator from Logic Rail Technologies.



Yellow displayed by Ligitek Electronics Inc. part LHG 2063 driven by a Signal Animator. Note how far apart the red and green dies are?



Yellow displayed by an ORS stock LED driven by one of Rob Paisley's 556 Signal Driver boards. I can probably learn to tell it from Red, but I don't think I can expect that from my operators.

I will follow up once Mr. Paisley answers my question about adjusting the color.

The eastern half of Bexley's signal plant is now in service, including CTC on the single track and the yard exit dwarfs which I hope will help my operators.



Most of my hobby time over the past 10 weeks has gone to signaling, so I feel like a break. I'll clean up the layout, have an op session or two and work at a slower pace on the issues in my last two posts.

Regarding Rob Paisley's 556 signal driver boards, he thinks if I spend a little quality time under the layout with my scope, he may be able to advise me how to tune a better 'yellow' output. I'll update.

The Eastern Route's signal plant worked flawlessly throughout today's op session. The operators liked it, and there was a good deal less 'feeping' from my PSX DCC circuit breakers in signal territory. But I'm pretty busy through April, so I'm not sure when the signal crews will return to Bexley and Lynn.

Sounds like Good News to me, James! Congratulations!

As to the signal crews, well... they don't get "spring break," so keep an eye on them and try to keep them out of the bars and on the railroad!

Pete

in Michigan

I had no thought of signals when I built all the main track on my layout. I knew I liked them, but I hadn't thought about the technology or infrastructure. Part of the price is visible below:



I had used 3PDT slide switches for two locations where I wanted a manual turnout to control a 'swing block' ('X Section' in Paul Mallery's book). One pole powers the frog, the other two select which block's power is fed to the swing block. But if these turnouts were to be protected by signals, I needed another pole.

I found 4PDT slide switches with a reasonable operating force. But they were larger and had a longer throw than the 3PDTs I'd originally installed. So I spent a number of hours under the layout rebuilding two turnout mechanisms.

More when I make one last decision about the 'Saugus River Draw' interlocking (E. end of my staging yard).

I finalized the Riverworks (Draw staging east end) interlocking yesterday and built it this afternoon:



Eastbound and Westbound are separate and almost identical in this instance. EB uses a two-light dwarf with the bottom head fixed.

WB will get a three-light home signal with RYG on top and RY on the bottom for entering the 'non-signaled' staging tracks 4 and 6.



I could have built the two sides on separate boards, but it was a little simpler with only one set of +/-12 VDC terminals. Next is to

mount it and build/install the remaining signals.

This diagram shows the color/circuit mapping and wiring for the EB dwarf signals that actually works.



And the interlocking panel, after I figured out that the 'common' terminals for the 4PDT relay contacts are on the side with the coil terminals (bottom in this photo).

I've mis-read/remembered the little diagrams printed on the clear housings at least three times in the course of this project.



Only the top head of this NJI dual dwarf needed a red/green LED, so I'd saved the manufacturer's red LED in the bottom position.

All was well till a lead pulled off when I was installing it on a styrene base.

I went outside and split some wood, but came back to it late in the afternoon. Luckily there was somewhat of a blob of solder on the terminal

that lost its lead, so I was able to re-solder without disconnecting the other leads.

The westward home signal is a bit up in the air. I've built a number of ground-mounted 3-light home signals, but this one would have to go between two tracks.



I don't recall any commercial offerings of what the B&M called 'bracket arms', but I could build one. Probably out of brass, because I've

seen the beating plastic signal bridges have taken on other people's layouts. But that won't be done in a day...

I got a little prototypic eye-candy out of extending the signals through Draw staging. The Newburyport West stagger block shows:



Clear



Caution



And now Approach Medium.



The signal driver for the top head (17wH in the diagram) used to get its Yellow Input from the signal in advance (16w) being Red. Now it gets Yellow when either the next signal OR the one after it is Red. The two diodes connected to the YI line implement that:



With the black band away from the Yellow input, it will get pulled down when either diode sees Ground on its line. Same thing is happening with the Red input of the lower head (17wM).

After I got that working I built a 4-detector board for West Lynn, but pre-snow shopping and the distractions of being a small-time author prevented me from installing it this evening. Tomorrow it should make a nice excuse for not driving in the expected frosty slop.

Eye Candy, Indeed! And this kind doesn't make me gain weight!

Very nicely done, James! Inspirational!

Pete

in Dark Territory

in Michigan

Last winter (near the top of page 5 of this thread) I mentioned that the westward end-of-double track home signal (9e1) at D'Arcy Ave.

wasn't doing Middle Yellow right. It's complicated because the next westward signal (7e1 at Enginehouse) has two active heads, High

for the straight route at the west end of the Tunnel, Middle for diverging. I could have done it with two transfer contacts, but that

gets complicated quickly.

Happily, I (a non-EE) had found out that Diode-Resistor logic could AND the Red inputs for the 7e1H and 7e1M together - only if both are Red

should 9e1 show Yellow. Last night I'd gotten far enough with Saugus Jct. that I needed to draw two of these AND gates. So I spent today

figuring out how to implement one that worked:



If either 7e1Hr or 7e1Mr is logic high (more than about 6 VDC), the diode passes it faster than the 100K Ohm resistor can draw 9e1My

down. Only if both are logic low (0-2 VDC when I've measured it), does the 100K resistor succeed in pulling 9e1My down (active).

The first I built was outright wrong. I experimented with the 2nd till I got the resistor right - 10K was way too small, 82K

worked, 220K was too big. In the middle, I chased a flaky in the occupancy logic at the other end of the tunnel - Problem Disappeared

In Diagnosis is an unsatisfying way of closing a ticket if you know you're in line for it next time it pops up.

So now back to drawing my layout's last interlocking.

This all sounds way above my pay grade, James, but if you're happy....

Congratulations, I think, and keep going!

Pete [:-cold]

in Michigan