Upper Deck Mainline Complete

At 2232h tonight, Friday, June 12, 2015, I joined the rails of the upper deck mainline to the south Chitina control point switches.  That, folks, means the mainline rails are continuous all the way from the mine through the bottom of the helix, completing the upper deck mainline.

That’s not to say there’s not yet work to do.  I need to finish the yard tracks at McCarthy and Chitina.  I’m hoping to at least get part of Chitina done this weekend, depending on how much real life gets in the way.

Weekend Progress – Strelna

I didn’t make as much progress over the Easter weekend as I’d hoped (so, pretty much par for the course), but I did get the end of track moved forward as far as the south Strelna control point.  I also installed the first pieces of backdrop.

Strelna, A Very Brief History

Strelna, in reality, was a rather boring place.  The real station had a water tank located south of the mainline and west of the low trestle over Strelna Creek.  Near the tank base was a switch that lead to two spur tracks to the north-northwest, one ~530′ long, one 634′ long.  Just a bit past the spur switches was the east siding switch, a ~1350′ siding, and the west siding switch.  The station was a small – single level, probably two rooms given the freight door on the west end – and appears to have been situated between the siding and main near the east siding switch.  There was also what appears to be a motorcar shed to the south of the tracks, across from the station.

Strelna was often mentioned in the early days as the potential start of a branch line to the copper prospects to the north of town.  The major player was always the Hubbard-Elliott copper prospects, located about 16 miles north of Strelna and over the ridge on Elliott Creek. The Elliott Creek basin apparently did produce somewhat, with the ore begin hauled down to the railhead at Strelna, but I have so far been unable to find any production numbers.  Various sources mention both a surveying a 17.5 mile branch line and a 17-mile tramway linking the mines to the CR&NW’s mainline.  The branch would come in just west of Strelna, at a location sometimes designated “Elliott Junction”.

The Hubbard-Elliott claims never seem to have amounted to much despite their oft-touted prospects.  The concern was still reported in limited operation in the early 1920s, but beyond that there is little record.  I suspect either the claims were exaggerated, or the brutal weather, poor financial backing, and lack of transportation access doomed them.

There was also exploration and development work done on Nugget Creek, about an equal distance east-northeast of Strelna, near the headwaters of the Kuskulana.  Nugget Creek interested prospectors – and got its name – from a two ton native copper nugget found in the streambed.  However, exploration never produced much – a few hundred tons of ore at the most – and Nugget Creek was abandoned by 1916.

Strelna on the Layout

Strelna – the model version – got a bit of a redesign over the past week from what I originally drew in the plans. I wanted to reflect the possibility that the copper deposits were proven viable, probably by SX-EW extraction rather than traditional milling and concentration, but I didn’t want to model another fictional branch or have Strelna turned into more of a town.  Basically, I wanted it to remain as a decent size passing siding and a handful of industry tracks for inbound materials and outbound mine products, but little else.  Strelna just isn’t far enough from Chitina to justify any duplication.  Anything Chitina would provide – such as fuel oil, LPG, etc. – would just get trucked to Strelna.  Duplication of facilities wouldn’t make any sense.

The model version isn’t as unfaithful as it might seem at first.  I started with the prototype – a siding approximately 1350 feet in length, or roughly 8.5 feet in N scale, located on the north side of the mainline.  (North, in this case, is towards the aisle.)   The 8 ft siding fits perfectly with about the maximum size of ore trains I want to operate.  The siding, like all major sidings on my present-day CRNW, will be controlled via CTC.  I plan to place a set of culverts just past the north siding switch to cross Strelna Creek, and put concrete tank footers up close to the culverts to mark where the tank used to live.

strelna-trackdiagram

The prototype of Strelna had two short spurs north/east of what I’m referring to as the “north siding switch”.  These were likely used as tracks to set out supplies for the mining concerns to the north and northeast, as well as for the hotel at Strelna (which burned in the late 1920s).  I’ve decided to move them halfway down the siding and expand them to support a theoretical producing mine based around the idea of the Hubbard-Elliott properties being developed, though on a much later timeline than Kennecott.

Given that I don’t want to model another entire mine complex, I’m going with the idea that the “new Hubbard-Elliott mine” is mostly solvent extraction, and therefore doesn’t load out concentrate or raw ore.  It only loads out copper cathodes, which will be transferred – truck to boxcar – at a facility on the “loading track” spur.  As far as inbound loads, most will be extraction chemicals (primarily sulfuric for running the SX-EW leaching process), blasting agents, and fuel.  The occasional load of heavy equipment or construction supplies would be completely reasonable as well.  These will go into the two offload tracks, where they’ll be transferred to trucks for the return journey to the mine.

The pictures aren’t the most current – I took these two weekends ago.  Since then I’ve finished the Strelna spurs and started wiring the whole mess, which involved putting a double-wide electrical panel under the south siding switch area.

Searchlights!

The real CR&NW was completely timetable & train order operations, with no block signals of any kind.  There’s a lone, uncredited reference in Wikipedia about the CR&NW having at least one “wigwag” crossing signal, but I’ve never seen any evidence to support this.  Given the limited number of trains operated and the generally poor condition of local roads at the time, I sincerely doubt that the CR&NW ever had a single circuit for anything.  At least as of 1920, this is confirmed by the ICC’s “Annual Report on the Statistics of Railways in the United States”, where the CR&NW has nothing under the cost line items for “Signals & Interlockers” and “Signals & Interlockers – Depreciation”, and “Crossing Protection”.  There’s the possibility of them coming later, but I still doubt it.  (I would love to be proven wrong, however.  Anyone?)

Update (Oct 16, 2017):  Turns out, I’ve been indeed proven wrong!  See Robert Hilton’s comment below.  There’s a photo in an old Magnetic Signal Company catalog of an overhead, lower quadrant wig-wag in Cordova on page 9.  Now I have a plausible reason to build a working wig-wag for the layout.

The model CR&NW however, having evolved into a modern heavy ore hauler, would almost certainly have block signals.  In my “alternate history” leading to the present day, the railroad underwent extensive modernization and reinvestment in the late 1940s / early 1950s.  Radio dispatch (which didn’t become widespread until the 1960s-1970s anyway) would have been nearly impossible, given the remote country and deep canyons traversed by the line.

For inspiration, let’s look to a pair of near-contemporary prototype ore haulers in the far north – the Quebec, North Shore & Labrador and the Cartier Railway (Quebec Cartier Mining or QCM).  The QNS&L was built between 1951-1954 and was equipped with CTC from the start.  The Cartier was built several years later, in 1959-1961, but it too was equipped with CTC from the start.  Clearly equipping a remote ore line of a few hundred miles in length with CTC isn’t beyond the realm of feasibility.  Plus, I have a serious fascination with signalling, so…

A Showcase Miniatures N scale searchlight signalGiven a modernization date in the 1940s/1950s, searchlight signals would have been the standard of the day. (Again, looking at the QNSL and QCM, it’s searchlights all around.)  The US&S H, H2, H5 and GRS SA were both extremely popular and were the most common type of signal installed all over the US and Canada during the 1940s through about the 1980s.  Recently they’ve been falling in record numbers, as their inherently mechanical color changing mechanism (a relay with three small color lenses) requires regular inspection, testing, and maintenance, as opposed to modern three-light heads.  The preference for searchlight type signals works out just fine with me, since they’re probably my favorite signal type and they minimize the number of wires or fibers that need to go to each head. Showcase Miniatures / Century Foundary makes an absolutely beautiful N scale searchlight kit. They’re lit with fiber optics, which allows them to be very accurate in terms of scale. (Oversized N scale signals really, really bug me…) I’d purchased a couple of their kits some time ago, so I pulled one out tonight and built it. It really is a work of art and not nearly as hard to assemble as I’d feared.  (I still have some fear of doing a double or triple head…)  I didn’t feel like breaking out the airbrush, though, so it’s unpainted for now.

The problem is then feeding light into them. Railroad signals have a unique color to them that’s often not captured by LEDs. The AREMA standards (Communications & Signals Manual, section 7.1.10 – “Chromaticity”) require green to be between 498-513nm, yellow to be between 589-597nm, and red to be 627-660nm. Very few 3-color LEDs hit this or even get close, particularly for green. One of the few that gets very close is the Bivar SMP4-SRGY. It’s a small PLCC4, with wavelengths of 525nm, 591nm, and 631nm. To my eye, it looks nearly dead on for the prototype colors. The PLCC4, while fairly small, would still look huge on the head of an N scale signal, and would need four wires running down the mast.

A board with two SMP4-SRGY leds on it for driving two searchlight headsSo, given that my signal models of choice are based around fiber optics, I created a board with two LEDs on board and holes for clip-in light pipe holders that fit perfectly over the LEDs. (The light pipes are Dialight part 515119200550F if anybody cares.) A Showcase Miniatures searchlight connected to the LED board by fiber opticsI can then drill a small hole in the light pipe and glue the fiber into it. The signal LEDs and their wiring (attached through an RJ45 jack for easy connecting) stay attached to the layout, and the signals can be installed and uninstalled with the ease of just connecting or disconnecting the fiber and light pipe.

bcol3902-and-signal.jpgonlayout.jpgGiven their fragility, the actual signals will be one of the last things installed on the layout.  I’ll build some temporaries for initial operations and testing.  The LED boards, however, will be installed as part of the signal system.  I did a temporary install (using the power of electrical tape to hold up the signal) at one of the block boundaries tonight just to see what it would look like.  In the final install, the light pipes will be painted black to eliminate leakage, but as I said earlier – wasn’t in a painting mood tonight.

Random Early Kennecott Photo

I don’t really have anything to share about progress on the railroad (my biggest achievement was stringing track power to the track from Gilahina to Strelna), but I did recently acquire an old photo of Kennecott that I’ve never seen before.  It’s clearly from the very early days, as the power plant isn’t built yet and the mill is under construction.  Thought I’d share it with y’all…

kennicott-2

Yes, there’s even more detail in the photo than the medium resolution version the thumbnail links to – you can read the text on the ends of the cars.  However, that version is huge.  If you want it, email me.

Benchwork Reaches Third Crossing

I haven’t had time to take pictures yet, but before I left for Chicago, the benchwork is now all the way through Strelna and at the northeast end of the Third Copper River Crossing (the one east of Chitina).   Unfortunately, in addition to being out of town, I’ve suffered a few other setbacks.  The 500′ spool of 14 AWG DCC bus was stolen shortly after being dropped off on my front porch by the delivery guy, so I’m out of wire for a couple days, and I’m waiting on more flex track and turnouts.  Because of those two items, it’ll be a few days until rails catch up with the benchwork, but I’m hoping by the end of March to have the upper deck mainline connected to the helix.

Pictures when I get back to Colorado.

First Train Reaches Gilahina

It’s really amazing how long it takes to do things sometimes.  I honestly hoped I’d be where I am now almost a year ago, but hey, life gets in the way, right?

At least I’m finally making progress on the mainline.  As of 1900h tonight, the first train reached Gilahina – or at least where the new Gilahina bridge will be in the future.  Sure, the electrical isn’t complete that far out (power was provided by clip leads) and there really wasn’t any complex trackwork in that stretch, but I’m still happy that I’ve finally got mainline down and can run trains more than over a few switches.

Saturday Progress

I’ve had a number of other things going on over the weekends (or it’s just been too darn nice to not get one of the convertibles out for a drive – pass up a 75 degree day in February, I don’t think so!), and haven’t felt like I’m actually making much progress lately.

This past week marks an end to the unproductive streak.  I’ve completed the roadbed from Nicolai Junction to the south siding switch at Strelna.  Track now extends down as far as the McCarthy end of the Kennicott River bridge.  I’ve also placed temporary bridges in the three large gaps – the Kennicott River crossing, the new Gilahina bridge, and of course the famous Kuskulana bridge.

I have other matters to attend to tomorrow, but I’m hoping to find a few hours to work on extending trackwork.  I’d really like to see the end of track at Strelna early next week.  At this rate, it may yet be possible to achieve my goal of track and electrical complete by summer.

Pictures tomorrow, after I clean up the disaster I’ve created in the layout room…

Progress – Rails Reach Kennicott and Nicolai Jct

I finally feel like I’m making progress again.  For the last three months or so, work has just been beating the snot out of me, and I haven’t had as much time to work on the layout as I would have liked.  However, that’s now starting to improve, and the mainline is starting to appear on the main layout.

The first matter is a bit of a track plan change.  You’ll notice on my original track plan, Nicolai Junction – the place where the fictional Nizina Branch breaks off the prototype mainline – was originally pretty inflexible.  Because the single track mainline split into the siding and main for Kennicott, and then the branch broke off the siding, the whole thing could get jammed up if you were loading a train at Kennicott and it was fouling the switch.  Plus, the McCarthy siding was short, so it wasn’t capable of holding a full ore train.  So, the track plan adjustments begin…

I extended double track up from the McCarthy switch, made one mainline diverge as the Nizina Branch and the other diverge as the Kennicott main, and then connected the Kennicott siding into the mainline.  There are also crossovers between the two main lines going both ways, so that traffic moving off any line can move onto any other line without being blocked.  The new Nicolai Junction will also now be the northern end of CTC on the layout, extended up from my original plan of ending it after the north siding switch at McCarthy.

Here’s the new line diagram:

mccarthy-nicolai-kennicott

I’ve also completed the tracks in front of the old Kennicott mill, and posted a 1:160 print of the mill for scale and alignment.  I intend to model the old mill at full scale, as one of the signature elements of the railroad.  To make sure it was going to fit, I printed 1:160 versions of the front and side elevations of the mill – based on the National Park Service CAD drawings.  Thankfully work has a large HP plotter which makes this much easier…

The electronics for Nicolai Junction are being installed on a fold-down panel located below the junction.  That way the wires all stay up and out of the way, the LEDs don’t shine down on the lower deck, but it can be lowered if maintenance or changes are needed.

Now, about turnouts…  Originally when I started the CR&NW, Atlas code 55 was still nowhere to be found due to their Chinese production issues.  Because of that, I made the decision to go with hand-laid turnouts using FastTracks tools.  However, it’s taken me far longer to get to trackwork than I initially expected, and the Atlas turnouts are now available again after about three years.  While the hand-laid turnouts look incredible and work well, they’re painfully time consuming to build.  The two in front of Kennicott took me a solid afternoon to build and tune.  Consequently, I’ve decided to use them where the switch is a prominent foreground visual element (such as in front of the mill building), but just go back to good ol’ Atlas switches elsewhere.

That’s it for now.  Hopefully by the end of the week I’ll have track extended down to the McCarthy control point and some of the backdrop up, so it’ll look a bit more like a model railroad and less like a bench stuck to framing.

 

Miles Glacier Bridge and the CR&NW Model Ts

The CR&NW seems to have had at least one, possibly multiple, Ford Model Ts converted to railroad wheels.  One of my recent acquisitions is this old CR&NW snapshot of a gentleman and one of the Model Ts (looks to be a later version, based on the larger radiator) posing in the middle of the Miles Glacier bridge.

Note the larger radiator and the single large headlight mounted on the driver’s side.  Contrast this with the smaller radiator and different headlamp arrangement found in a photo of Walter Angier posing with another supposed CR&NW Model T in 1919, as posted on Cora Sowa’s website about a sixth of the way down this page.

I’m not a Ford Model T expert by any means.  However, given what I can dredge up, both cars appear to be 1917s or later, based on the black steel radiators and other design changes.    However, either there have been some serious modifications to the same car between the two images, or the railroad had at least two of these critters.

Auxiliary Power Converters

Like most layouts, the CRNW will need a variety of voltages scattered about for turnouts, signals, structure and scenery lights, etc. I’ve seen various solutions to this problem over the years, ranging from a single auxiliary power bus with local regulation, to multiple aux power buses running at different voltages, to the worst of all possible options (which I’ve seen on more than a few layouts): various old power packs, wall warts, batteries, scattered all over the place to power everything.

Myself, I’m a single aux power bus sort of guy, with point-of-load regulators to deliver whatever voltage is needed. That way, I can delivery 8-9V for MRBus and MRServos, 3V for structure lights, 12V for local NCE cab bus power injection, etc. and only have to run one large, high power bus around the layout to feed everything.  My traditional preference is to run the aux bus at a nice 24VDC.  That means using linear regulators for local voltage generation is pretty much out, as you’d burn a huge amount of power in the regulators.  As an example, take the Nizina Yard and its two MRServo-2s.  They’ll need ~8VDC, and will each draw ~50mA just sitting there if the relays are on (as they’ll be for one direction or the other).  That means the two turnout motors will be drawing 0.8W (8V * (0.05A * 2)), but the regulator needed to create the 8V will be burning 1.6W ( (24V – 8V) * (0.05A * 2) ).  That means that my point-of-load regulator is only 33% efficient.  And it only gets worse from there.

The answer to this is something called a switching regulator (aka a switchmode power supply or simply “switcher”).  Basically, rather than burning off the excess electrical power as heat, switching regulators convert that excess to a magnetic field.  For some small amount of time, they’re switched on, powering the load and storing excess energy in building the magnetic field.  Then they switch the input off and power the load by collapsing the magnetic field.  If you change the ratio between the on and off times and do it very quickly, you get very good regulation and a large percentage of the power actually gets delivered to the load.  It’s not uncommon for switching regulators to be 90+% efficient, which is why they’re becoming common everywhere.

The problem with switchers is that they’re much more complicated than linear regulators, and thus typically more costly.  Fortunately, Chinese manufacturers do things on scales that boggle the mind and do it with parts that are sometimes of questionable heritage, driving costs to an insane minimum.  Popular on eBay are switching converters based on fake National Semiconductor (now Texas Instruments) LM2596 parts.  Often available for around $1 in small quantities, these are a full, adjustable output switching converter on a small PCB, including the control chip, inductor, input and output capacitors, diode, and a potentiometer to set the voltage.

Typical eBay fake LM2596 module

Typical eBay fake LM2596 module

However, now’s an appropriate time for a disclaimer.  One of my favorite quotes from a movie character is from Burt Gummer (played by fellow model railroader and actor Michael Gross):  “The possibilities for disaster boggle the mind…”  At the prices offered for these boards, the LM2596 parts used are almost unconditionally fake, Chinese cloned parts, thrown together into a module where every corner has been cut and every substandard part has been used to minimize costs.  As such, it doesn’t behave like a real quality National/TI part, specifically when you start pushing the limits with regards to current and temperature.  Specifically, if they get too hot, they don’t shut down like a real one.  They just short, sending full input voltage to the load.  If your load can’t handle it, it goes up in smoke.   However, I’ve used a lot of them on various model railroad applications over the years, and as long as you use them conservatively (meaning don’t do more than 1A continuously), they do work and work well for $1.

eBay MP1584EN module

eBay MP1584EN module

A new module started appearing on eBay a couple months ago – a much smaller design, based on (theoretically) a much more modern switching chip.  The chip appears to be an MP1584EN from Monolithic Power Systems, and the board is about the size of a quarter.  Again, they’re available for about $1, which makes no sense at all, given that real MP1584EN parts are over $1 even in 10,000 unit quantities, and that doesn’t take into account the other parts, the board, or putting it all together.  Either the Chinese got a hell of a steal on their parts, or once again we’re dealing with a cloned part.  So what did I do?  Order a dozen of them for evaluation, of course!

In the usual 2-3 weeks, a bag showed up in the mailbox with a whole bunch of the little modules in it, each individually packaged in an ESD protection back.  Each module is about the size of a US quarter – exactly what the dimensions on the original eBay listing promised.  However, the holes are not exactly where they were specified to be – the upper and lower groups are 30 mils too far apart and the right and left groups are also 30 mils too far apart.  Otherwise, they’re pretty unremarkable.  So, the next step was to solder up wires and beat them up electrically to see if they’d survive layout use.

The test setup involved a bench supply pushing 24V, meters for input voltage and current, a meter for measuring IC temperature on the switching board, and then a programmable current load (the Re:load Pro from Arachnid Labs – a remarkable piece of gear for the pricetag) for actually sinking the power.  Oh, and we’ll throw my scope on the output to check for ripple as well.  What you wind up in terms of bench litter looks something like this:

The test setup on my bench

The test setup on my bench

The first one was dead, straight out of the ESD bag.  It had quiescent current draw (200uA or so) but no output.  Didn’t matter if I twiddled with the pot or anything, it was just pain dead.  I suspect the IC itself had a bad power switch, as I couldn’t see any voltage on the output to feed the inductor.  Well, write that one off as a mechanical sample only…

The second one fired right up and did exactly what it was supposed to.  For the simulation, I chose 24V as the input voltage, matching my planned accessory bus, and 8.5V as the output voltage since that’s usually what I feed to MRServos and to the MRBus network.  At each current step, I’d set it and go do other things for five minutes to allow the temperature to reach steady state.  (The room was approximately 68F / 20C during the testing.)

Here’s the raw data:

Target Current Vin (volts) Iin (amps) Vout (volts) Iout (amps) Tsteady (deg C) Vripple (mV rms) Eff (%)
0.25A 24 0.1 8.47 0.249 31 11.9 87.9
0.50A 24.1 0.196 8.45 0.499 35 15.8 89.3
0.75A 23.8 0.296 8.43 0.75 41 16.1 89.7
1.00A 23.5 0.398 8.41 1 47 16.6 89.9
1.50A 23.9 0.588 8.37 1.5 53 18.2 89.3
2.00A 23.2 0.817 8.31 1.99 69 20.1 87.2

At 2A, the part was right on the edge of thermal limiting.  It would cut out for a few fractions of a seconds every 5-10 seconds.  Above 2A, it was in thermal limiting more than it was out.  So realistically, running these at 1.5A would seem to be a safe maximum.   Efficiency is also decent – ranging between 87-90% for my test cases.  Not bad for a $1 converter board.

On the other hand, the testing proved that thermal limiting does indeed appear to work.  Additionally, I subjected the part to repeated short circuits on the output with no apparent harm.  It gives me some faith that if this is a cloned control IC or at least one that failed some part of QA (and I have every reason to believe it would be, as discussed earlier), that these actually will function well enough to meet my needs.

Because these boards won’t be very handy to work with directly, and I have a rule that any switching converter hanging off the high current auxiliary bus have a fuse (since a tiny board like this suddenly dissipating 200W+ (10A@24V, my fused limit back at the power supply) seems really bad), I’ve designed a carrier board for them that includes an input filter cap, a ATO-style fuse holder, terminal blocks for the input and output, and a “power on” LED.  Pretty simple board, really, but should make working with these things a lot easier.  It’s off to fab right now, but I should have it back by Christmas and can report on it as well.