The bones are finished

Day 2 of the Last Week of the Year:

I’ve had much of my benchwork in place for a couple of months now (see  this post), but today I finished the base structure for the layout.

Last Sunday I got help to pick up several sheets of Homasote and one more sheet of plywood (thanks, Dave).  Today I picked up several more 1x4s and 1x3s (Menard’s Black Label select pine — nice stuff), and I finished up the last section of L-girders, plus the joists for the subroadbed.  It’s nice how quickly everything goes when you’ve got a plan and all of the tools readily at hand.


I do need to add some braces between the legs and the girder, but that’s another run to Menard’s (1x2s).

The plywood is in place, the Homasote is all cut and in place.  I’ve even got some temporary fascia installed.

Now to do another solid round of dust cleanup, and I’m ready to start making some progress on something above the benchwork for once.

IMG_0591 IMG_0592

The railroad work week has started

Every year I take the week between Christmas & New Year’s off from work[1], but I stay at home and usually work on my railroad.

This year I am happily continuing this tradition.

Yesterday I got rid of an old couch (one that’s been with me for over 35 years – probably 15 different dwellings in 3 states).  It’s been in my basement for many years now, and the space it takes up has too rarely been used for sitting and more likely used to pile stuff.   I had to remove the handrails to the stairwell and move a bookshelf in order to fit the sofa up the stair well.  It was a tight squeeze, but Max and I got it up the stairs and out into the garage.

I then put a bunch of other things away, making room to move things around now that the 8 foot long couch was gone.   It’s amazing how much more space I have in my basement now.

So yesterday was cleaning.

Today was benchwork, about which more will be posted soon.

I hope to actually have some track laid and operating before the end of the year.



Note 1: This stems from one year, one of my first in the full time working world, where my boss did not allow  me to take my planned vacation because the release wasn’t done on time, even though the person who didn’t get their stuff done did go on vacation.  So I (the release engineer) made the release on December 25th, which was encoded in the version number that every customer saw for  the next several months (until the next quarterly release).  Boss took no small amount of crap from customers who wanted to know why the company forced someone to work on Christmas.   The following Christmas my vacation request was granted, and thus the tradition was born.

The jig is out

I’m using L-girder benchwork, with fairly large areas of flat ground (since most everything prototypically should be around 15 feet above sea level, if that).   This would normally entail risers with cleats on them, so I can drive all of the screws from below.   The main reason to use L-girder benchwork is the ability to move risers & joists as needed, and that is hard to do if you drive screws in from the top.

I dislike using cleats on the risers — it’s not that hard but it can be kind of fiddly.

I also have the luck of being able to use most of my joists as the riser as well, since most of the lumber I used to make the joists was cut at the same time so they’re the same height.


Time to dig out the tools.  I have a jig to make these nifty pocket holes, and they work beautifully for driving the screws from below.   This joist is a bit smaller than most, so it’s attached to the leg and not the L-girder.

The jig holds the board securely and has a guide for a special bit.  Everything is set “just right” for the pocket hole to be drilled and a pilot for the screw placement.  A bit of sawdust is created, and you’re ready to drive the screw and hold the joist to the plywood.



I placed several pockets to attach to the boards above.  No part of the screw protrudes above the surface of the plywood when they’re driven.



I think they’ll all be out of the way as I need to drill switch throw holes in order to place the switch motors, but if not, I’ll just move the joist.  That is the beauty of the whole L-girder system after all.

The jig is from Kreg and can be ordered online or from your favorite local hardware store.


Boards in the mail

My order for the RSMC boards came in the mail today.

I love how this works — I upload the Gerber files which define the board layers (copper traces, plating, thru holes, mask, silkscreen, etc) and in a couple of weeks I get the boards in the mail.  In this case, I used the files created by Chuck Catania & Seth Neumann out in the Bay Area, but you can use circuit design tools of all sorts to generate the appropriate files.   I’ve used the Eagle CAD tool, which is free (as in beer) to use when the board is small enough (about 4″ x 3.2″, which is a pretty decent size).

RSMC boards

The order was for 50, but I guess that 52 fit the manufacturers process, since that’s what I ended up with.  Oh, darn, free stuff.

For the record, I use the Seeed Studio PCB process.  I’ve had my cpShield boards made by them as well, which are a CMRI interface shield for Arduino boards, and now these RSMC boards.

I’ve had all of the parts I need for a while now (Digi-key and Jameco ship much faster than parcel post from Shenzhen), so now that I have the Tortoises ready, I can start building the controller boards.

More of the sweet smell of solder….. (blech).

Switch Motors Ready For Use…

Switch motors ready for use...
Switch motors ready for use…

I’ve been cleaning up the boxful of used Tortoises that I got at the last State Fair flea market.   I’ve removed the wires from each one, cleaned up the contacts, and soldered on a header block.  It’s my green frog version of the Terra Cotta Army.

Header Block

These headers are .156″ spacing right angle headers, which are designed to work with Molex connectors.  They work well enough on the Tortoise — whoever designed the board at Circuitron made something that almost, but not quite, works correctly with standard connectors.


I used to use the EDAC connector plugs (available from Greenway), but these are $7 or so apiece, and they only mostly work.   They can be installed off by half a pin or so, which causes them to not work reliably.  They also can slip off due to vibration, since the board on the Tortoise isn’t the same thickness as the plug expects.

I’m going to use the RSMC (Remote Stall Motor Controller) board, which will take a logic hi/lo signal (such as from the Arduino, or a single pole single throw toggle/pushbutton) and swap the polarity on the 12V power to the tortoise.     These board have the matching connector to the headers I just soldered to all of these Tortii.

RSMC ImageI also can wire up the rail power to the RSMC, and I’ll get the correct frog power based on the switch position.  There are additional connectors that I can use for LED indicators on the fascia.

RSMC Installed

I have all the parts for the RSMC boards on my bench, except for the PC board.  I’ve ordered them from Seeed Studio in China, and they’re somewhere on the way between Shenzhen and here.   The total cost of the board, the components, and the connectors will be about $5 each, which certainly compares favorably to anything which uses the EDAC connector.

There’s a different edge connector available in the last few years:


This one fits a little better, but not so much that it really is much better.  It does have the advantage of being easier to use on a circuit board (the Hare, of which I have one for testing, uses this connector).  It’s also a little bit cheaper (about $3 each).

But nothing beats the solid connection you get from the Molex connectors.  Combined with screw terminals for the other connections, I like how the RSMC is fairly easy to replace if necessary, and I don’t think they’d slip off in a Richter 8 earthquake (something my friends in California might worry about, but I don’t here in Minnesota.  Thank goodness for that.)

Maybe I should get started on laying track, so I have someplace to use these sometime soon.

New Arduino code posted

One thing I do besides build & operate railroads is mess around with Arduinos.  These are small low-cost low-power computers that are really good for messing around with.

I’ve designed an add-on board called the cpShield, which is meant to make the Arduino into a general I/O board, mainly for use as a part of a CMRI network for model railroads.  The cpShield has 16 general I/O lines, and can control a single stall motor (such as a Tortoise) or two servos.

There’s also an I2C connection for adding additional boards.   There are 16 and 32 I/O line boards called the IOX16 & IOX32 that I have used.

a cpShield board with an attached Arduino Pro
a cpShield board with an attached Arduino Pro

The blue board is an Arduino Pro (seen from the bottom), while the green board below it is the cpShield itself.annotated2 copy

I’ve also written code for turning this into a node on a CMRI network.

There’s a library called IOLine, which generalizes the notion of an input or output line between the Arduino pins, the IOX extender boards (which do the same thing, but with a different code interface), or internal variables.

There’s another to provide a decent interface to the IOX extender boards, which use an MCP23017 I2C chip.  The library is quite unoriginally called MCP23017.

Lastly, there’s code to implement the node side of a CMRI network.  You still need driver software on a central computer to run the network.

I’ve spent the last few evenings making lights blink with the Arduinos, and have recently updated the code out on Github.

Go, have fun with it

DCC on a Board

I didn’t have a good box for this, or else it would be DCC-in-a-box.

All of my interesting DCC bits are tied together in one place.


This board has three “upstream” connections: 2 x 120V AC (from the power supply brick and the terminal server) and one wired Ethernet (not shown).

Downstream (towards the layout) are connections for:

  • LocoNet (throttle bus)
  • Digitrax Simplex wireless throttle support
  • Rail A, B (DCC input to the circuit breakers that feed the power districts)
  • Programming A,B (with the Programming Track Booster in place)
  • Serial ports (via the terminal server) to the LocoBuffer and to the CMRI bus that will go throughout the layout.

The configuration shown here (except for the CMRI connection) has been built, tested and used for various locomotive projects while I was between layouts.   This makes the wiring of the layout a bit simpler and also makes it easier for me to trust that the basic DCC wiring configuration is good, and that any problems I encounter as I lay track and wire it up is due to the new work and not these components.

Electronics Shelf

I’ve put in a shelf to hold the DCC board.  I’ll have a separate switched circuit under the layout to be able to turn the layout on or off from a single point.   This switch will have a light easily visible from the main room entrance, making it hard to miss if I turn out the room lights and have left the layout on.

If you happen to care, download the DCC on a Board image as a PDF file: DCC on a Board


I had been wondering what to do about switch controls. Blue Points, servos, Tortoise, something else?


Found these at the flea market today. 50 Tortii, at a price that can’t be beat.

Modelling the Alley

A few days ago, I posted a map of the North Point / Beach Street “branch” of the State Belt.  Now, using my sophisticated planning tools, I’ve got a pretty good idea of what is going to fit in the space I have available.


These are templates from Fast Tracks for the size of switches that I plan to use.  The crossover is set up for 2″ track spacing, which suits what I need.   I have a pile of these printed up, and lay out track arrangements with these.

I’ve annotated the left & right hand templates with information for when I lay the track — I have a box of switch ties pre-cut to the necessary lengths, as indicated adjacent to each tie on the template.  I glue the template in place, then glue the wood ties to the template.  Then I can put the pre-built switch into place and I’m ready to move further down the line.


I also have built a number of building mockups out of about-to-be recycled boxes from work.  These range from 2 to 8 stories in height, and are about one half to one third of a block in size.  Since these streets have significant structures on each side, I want to get the feel of the visuals as well as the mechanicals of the track arrangement.

The picture above is North Point, running past several different industries (see the map link above).   I like using “false fronts” along the aisle to indicate that those are active buildings as well, instead of placing a spur right alongside the immense drop-off of the benchwork edge.  I used this in a couple of places on the St. Paul Bridge & Terminal, although I’m taking it up a notch with several buildings in a row.

I’m mixing taller & shorter buildings in front, in an attempt to provide suitable access for everyone to be able to reach in and uncouple cars as needed.   I’ll be putting turnout controls on the fascia (either Blue Point mechanicals or some servo controller), so no reaching in for ground throws.


This shows Pier 43 1/2, which is one of three car float aprons on the north end of the railroad.  Alongside that pier is a small yard which I can only imagine was used to stage cars for easy loading and unloading of the car floats as they came in.   I’ll have four tracks, which should be good for a three track float.  Further back is a small yard & team tracks, and off to the right would be Standard Oil, Harbor Warehouse, and the track to Ft. Mason & the Presidio.

The white rectangle is the mockup of the car float (for size).   I think that a small portion hanging off into the aisle is probably going to be okay.

This more or less accounts for one third of my available space.   I count 45 car spots, plus the float yard.

Now to work around the curves seen at the far end of this photo — double tracks following the Embarcadero along the various municipal piers and towards the S.P. interchange at King St.

Maps to follow.

These are some of my favorite things

I have several of each of these, and I use them much more often that I would have expected.

They’re simple weights.   Cut with nice square corners, so they’re more than just a thing to hold something else down.  I can use them to square up corners when I’m gluing them.  They’re used to brace things against.   They’ll hold the other end of track down as I spike it.  They hold wires on the top side as I work with them belowdecks.IMG_5410

I bought some brass bar stock many years ago (about 1″x2″ x 5 feet or so), and had a friend cut off several pieces about 6″-8″ long.   I still have one piece about 2′ long – not something I want to drop on my toes.

The larger one shown is a steel block, of which I purchased 3 or 4 at some modeler’s garage sale (alas, I don’t recall whose).

These aren’t precisely measured machinist’s blocks — the dimensions aren’t any nice even size.  I don’t know they’re weight, but I do know the brass one are NOT sized to anything other than “this looks good”.

They’re both heavy, as a weight should be.  I’d guess the steel weight at 5-8 pounds, the brass ones at 3-4 lbs. maybe.