Lineside Signals: B&M Eastern Route

[jbvb]

26-Jan-2016: MarkF and Orionvp17 complimented my work. Thanks, Pete & Mark.

My career included both 'out where the streetcars don't run' software engineering and 'explaining to co-workers so I don't have to do it all myself' teaching. From a process PoV, I've broken signaling up into manageable (IMO) chunks local to individual signals and interlockings. I did circuit diagrams for those who work that way. The photos of the interlockings show how they look in real life, with narrative replacing sticky labels and wire tags all over the place (you may see the labels & tags when I get to the bi-directional double track part).

3-Feb-2016: Detection was in place on 8 of my 16 main line blocks. Signals protected operation over 5 of them.

I finally got the Bexley CTC (Extending from Saugus Jct. to D'Arcy Ave., under control of the Train Director at Bexley Tower) drawn sufficiently to my satisfaction. And I started wiring it.

 

First came the simple interlocking at the end of double track (D'Arcy Ave.). Then the somewhat more complex one at Bexley Enginehouse (east portal of the tunnel). I'll probably have to revise the drawing to make room to document all the circuits between Bexley Enginehouse and Saugus Jct. (I split it into Bexley Tunnel and Bexley Tower).  It was clearer in XTrkCAD, but I ran out of screen.

10-Feb-2016: 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 of the Enginehouse area:



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 Tower, 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.

After posting I got back to work on the Bexley Enginehouse interlocking and its yard exit dwarf signals.

[jbvb]

Bulletin Order #17, February 9 2016:
Westward 3-light interlocking signal and dwarf signal for against-current-of-traffic moves off the eastward track at MP 12.5, D'Arcy Ave. have been placed
in service.

14-Feb-2016: I got the Bexley Enginehouse interlocking working that afternoon. It wasn't completely functional until I finished 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 diodes in my hand below OR turnout position+Oc7 with Oc8 for SD7e1M's Red input. Oc8 isn't affected either:

 

[jbvb]

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.

22-Feb-2016: 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, but didn't post again till both ends of the tunnel were properly interlocked.



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.

[jbvb]

FSS platforms (bottom) were 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 closed their doors for the last time around 2020. What I used here was from '8031 ladders & platforms'.

28-Feb-2016: Some recent progress wasn't perfectly executed:

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: (vanished from the 'net sometime after 10/2023):

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.

27-Feb-2016: 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.

[jbvb]

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 exchanged a number of emails with Mr. Paisley on this matter, including scope traces.

3-Mar-2016: 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 thought 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.

16-Mar-2016: 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.

[jbvb]

30-Nov-2016: 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.

6-Dec-2016: 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 (someday, when I take up my soldering iron and build what the B&M called a "bracket arm").



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.

[jbvb]

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 in an area with frequent switching.



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... (or even 9 years so far).

11-Dec-2016: I got a little prototypic eye-candy out of extending the signals through Draw staging. The Newburyport West stagger block shows:



Clear



Caution and Approach Medium.

[jbvb]

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.

16-Dec-2016: Last winter (near the top of this Modelers Forum page) 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

[jbvb]

20-Dec-2016: I checked several on-line model RR vendors for bi-color 3mm LEDs suitable for use with the Oregon Rail Supply
searchlight heads I've been using. Alas, I only found 4 of ORS' own #126 red/green LEDs in stock anywhere, and they're
$5 for two. Circuitron's red/green LEDs are $3.95 each.

Can anyone point me at a manufacturer part # with red & green dies (the light emitting bits) set close enough to make
a decent 'yellow'? Unlike the Ligitek 2062s I showed on 27-Feb-16?

Or has anyone like the results with a less expensive part, like those .LED-Switch used to have ? I have to order a few blue
LEDs for dummy masts (I'll explain that when parts are on hand to build the two 'bracket arms' I need), so it would only
be another $1.50 to try 10 of them. Life is short...

8-Jan-2017: The holidays, houseguests and travel left some room for progress on my signals. I completed the design for the last two interlockings and completed one:



Here's Saugus Jct. installed, with three of its four signals wired and operational. The easterly half of the crossover is Chipman St., still on the workbench being wired. Once it's in, four more mast signals remain to be built.

12-Jan-2017: Yesterday I finished installing the Chipman St. interlocking and connecting it to two of the three signals it drives. That was the last, so my signal project had reached another milestone.



The Saugus Jct. end of this diagram is different from the picture above; I didn't read my own documentation and so I had to invert the sense of relay R5T1. All I'd been able to get off Bexley Tower's antique key switches was a 'break' when the turnout was reversed. Because of the number of diodes involved, it was easier to shift two functions one contact set left.



Here's the final (at least through 2025) Bexley (Tunnel West, Bexley Enginehouse and D'Arcy Ave.) drawing, with wire colors, correct labels and a few obsolete ideas cleaned up.

Next I used parts on-hand to build the two 3-light home signals that will finish Saugus Jct. and Chipman St. I still don't have the brass bits for the 'bracket arms' required to finish West Lynn and River Works.

[jbvb]

13-Jan-2017: The night before I implemented these interlockings. Chipman St. (below) is the most complicated I've built, and it's a bit of a mess, mostly because of all the diodes I needed to logically OR multiple inputs to each signal driver's RED terminal.



The auxiliary terminals left of the top SD-3s are crowded, so are some of the main terminals and the relays' screw terminals.



I count 24 diodes in this interlocking. I drew them in a matrix, and it would have been much neater to wire it like diode matrices for yard throat control. But I'd had trouble with a matrix I built from perfboard and bare wires, so I wired this directly.

Question: has anyone found a commercial circuit board (probably for prototyping) that's a good base for building a matrix? Copper leads going one way on one side, perpendicular on the other, lead and hole spacing allowing diode installation somewhere between 1/4" and 1/2" apart?

19-Jan-2017: More progress the past few days:



The eastward home signal for Saugus Jct. with soldering complete. Red/Green bipolar LED for the High head, fixed Red Middle head, Red/Yellow bipolar LED to provide Restricted call-on into the Bexley industrial area. Finished it this afternoon (photo in B&M Eastern Route thread), three more to go.

18-Jan-2018: My signal system has been almost complete for a year now (except for two bracket-arm masts I haven't gotten around to
scratchbuilding). It's operated reliably; the only glitches were a couple of cases where a fine 'pole line' wire wasn't being well-gripped by my bargain euro-style terminal strips. When I do a 'DC Day' and run my older equipment, I do find myself wishing I'd used only DCOD detectors, but the places where I did operate just as I wish.

18-Feb-2018: Sometimes "act now" is the right path; I should have bought the Model Shipways etched brass numbers (page 1) for automatic signals back in 2016. Now it appears Model Shipways has been swallowed up by another firm and the 2mm and 2.75mm letter/number sets aren't to be found on the website.

I can get 1/8" from miniatures.com (oversize, but maybe more legible) and 2mm from secretweaponminiatures.com. Anyone have other suggestions? Europe/UK included, as I have overseas family who would probably help.

[jbvb]

27-Nov-2018: A few updates on my signals: Once in a while something on a contact gives an incorrect indication. All cases to date have been fixed by throwing the guilty turnout a few times, so it's usually one of the Kemtron-style switch machine contacts.

I was testing a prototype Spring Switch Controller from Azatrax:



This is the 'three wire' version, for use with Kemtron etc. twin coil solenoid machines. I added the outboard relays so the machine could be driven by my capacitor discharge supply. It has a rectifier but its built-in relays buzz a bit on AC. It's not on Azatrax's site today, but I understand it and the '2-wire' (Tortoise etc.) version should be available soon.

Like many other Azatrax products, it uses I/R LED and detector pairs to detect trains. I used the 'reflective sensing' mode, which was a little tricky where I had little room. It works well, but detection & throw take a moment: 2" from the 'branch' sensor to the rail gaps is OK up to maybe 40 scale MPH. I don't mind because the prototype limits speed to 25 MPH or less when pushing switchpoints over.

I had to update the Newburyport diagram to reflect this and the use of Rob Paisley's LED drivers instead of SD-3s:



I fixed several errors/omissions in labels too.

7-Jan-2019: I just got reminded I needed closure on getting a good 'yellow' out of a stock Paisley 556 signal driver card: LEDs I bought in 2017 from led-switch.com labeled '3mm Red/Green Diffused 2-lead' give a nice 'yellow'.  led-switch is now gone. I've got to test before buying any diode signal lamps in quantity.

17-Jan-2019: I learned that Free State Systems, who made the nice etched signal ladders and platforms shown earlier in this thread, is no longer in business. No inventory remains.

24-Feb-2020: In October 2019 I prepared a Lineside Signals clinic slide-show for an NMRA Seacoast Division event. I was reviewing it and realized an illustration I'd made was worth posting here:



This shows my layout's signaled main-line blocks.

3-Apr-2020: Rix hasn't had the complete CTC Knob kit the last couple of times I looked, but I ordered plates and knobs. There seems to be a spring which retains the knobs on the rotary switch shafts, but I can probably improvise that from street sweeper bristles or strapping off bundles of ties. Now that I have functioning spring switches, operations would be more realistic if I used knobs to set direction (East - Auto - West) on my two single track segments.

4-Oct-2021: At 8 PM Saturday Oct. 9 I gave my clinic about building this signal system at the Northeastern Region convention Mill City 21 in Westford, MA.

28-Oct-2021: I'd noticed a minor problem a while back: One light on a 3-head home signal never showed Clear (green), only Caution and Stop. I sat down (under the layout) last night with the diagram to diagnose it. I'd used female spade terminals for connections to the Circuitron SD-3, rather than solder, so first step was pull the Y wire off. It stayed yellow, so the problem was in the SD-3. I had another on the layout whose signal hasn't been built, so I swapped them.

Now both work. Maybe a bit of cut-off wire had fallen into it and moving it cleared it out, but a clear case of Problem Disappeared In Process of Diagnosis.