Designing a Roller Gauge

I have a request from a fellow Proto:48 modeler for some roller gauges. These handy things are just the ticket for handlaying track and, as far as I can tell, not something you can get for Proto:48. (There are commercially available gauges for most of the regular track standards) While I am not prepared to make lots of gauges on my entirely manual Myford lathe (You would want a CNC machine to do this commercially) I am not averse to knocking out a couple. Once I finished my Milling About and rearranging the shop…

Milling trials having been concluded (more on that later) and shop having been rearranged including new task lighting and a shelf over the lathe, I am ready to actually make something which leads us to objective of this post.

The relevant dimension of the target rail is the width of the rail’s head since that is the part the gauge has to fit over. The measurement reported for ME code 125 is 0.056″. The rest of the numbers needed come from the NMRA trackwork standard for Proto and Fine Scales S3.1. From the Proto:48 line we get a gauge range of 1.177-1.203, a flangeway width of .036-.039, and a minimum flange depth of .026.

From those numbers, we work down to something I can aim for on the lathe. I say aim because I can miss a dimension by a couple of thou and still get working gauge. A couple of thou is a long way in machining(famous last words).

• The desired target gauge is the middle of the standard so 1.190.
• We want the gauge to fit through minimum flangeways so .036 wide and .026 deep.
• We want the gauge to be accurate without being difficult to fit on the rail or roll along it. This suggests a loose running fit (had to look that term up) so I will add .003 to each slot to get .059. As a check, 1.196 is well within the standard’s maximum allowable gauge of 1.203.

Here is a very low tech sketch of the planned work:

Proto:48 roller gauge for ME code 125.

Keeping My Hand In

I use Templot to generate templates for hand laying track. Templot is a very powerful program that knows way more than I do about prototype track design. It also has a unique user interface that takes time to learn. My challenge is that I don’t create new track templates very often and so tend to forget a lot and have to relearn things.

I was therefore pleased when my friend Trevor Marshall asked me if I would produce a template for a simple Proto:48 test track he is contemplating. Since my entry into 1:48 scale was largely due to enablement by Trevor, I am happy to return the favour and enable right back at him.

I will let Trevor share the details of his project if and when he wishes but I will say that he is using different track castings that I have (more that one choice, we are spoiled!), different rail size and different frog numbers. All of that meant I was essentially creating the template from scratch rather than just copying the old reliable #6 I created many years ago.

After much googling for AREA standards, measuring castings with dial calipers (because my digital one’s battery up and died…), and poking about in the Templot menus, I achieved what I will call success. Because Trevor was mostly concerned about turnout geometry I forwent the refinements like shoving ties around, adjusting the length of guard rails and such.

I got it done and printed out in time for delivery at via dinner at the Harbord House last Tuesday. Pub based delivery best delivery.

Fixing The Last Turnout and Onward

Today I got the last “eighth” of the turnouts sorted. I resoldered the rail at the joint I broke loose last week, tweaked the alignment and aligned the servo. The servo alignment is good enough to work but just barely. I clearly goofed a bit when I sited the servo and bent the wire so maximum travel on one direction just gets to the stock rail. I will see how it holds up but for now, all of the trackage is operational.

I then set out to do a little cosmetic work on the trackage. It feels a bit odd to be working on purely cosmetic aspects of the track but I had to get there eventually. I started by filling in the ties around the front track baseboard joint where the rail is soldered to screws. I am not fussing over really tight fit since I expect things to get well buried in ballast and weeds. I am also using up scrap tie bits because who doesn’t save those for just such an eventuality! Nothing glued down in this shot, lower right bit is out of place for illustrative purposes.

After a break for glue drying, I masked the front track’s surroundings and sprayed the track with the base brown colour (Rustoleum Camo Brown). Additional colouring is definitely in the cards since the result looks like commercial flex track. No point in putting all those spikes and tieplates in if nobody can see them. You can tell where the soldered screws are since the paint dries a lot slower on the solder than it does on everything else.

 

87.5% Operational

Today I installed the links that complete the connection between throw bars and vertically rotating servo wires for the 3 remaining (of 4) turnouts. I bent them up on a (new) eye forming jig since I have lost track of the original one and mass produced the three before fitting them individually.

Installation required measuring and bending a 90 degree bend to match up with the hole in the end of a throw bar. In two cases, I had to drill out the hole to clear the music wire. I must have missed those in the assembly process.

Once the links were installed and a break was taken to deliver the mother-in-law to a church service, I set about adjusting them with the handy dandy alignment board that Tam Valley sells to go along with the Octopus servo controller. All went well for two of the turnouts but the last did not align properly for the diverging route, one of the ones through the diamond. Further examination indicates that the stock rail is not diverging at enough of an angle to allow the business end of the point to lie flat against the rail. I think I know how the geometry has to change but making it happen will be “interesting”. I tried to bend things a bit in situ and ended up breaking the solder joint at the baseboard edge nearby. Another break to retrieve mother-in-law and cool off was in order!

In any case, before I bodged up the solder joint, I managed to have the loco visit all of the layout under power with only the occasional nudge required due to dirty track. I figure of the eight possible routes through turnouts, I can 7 work hence the title. Here is the star of the show exploring the track in front of the traverser.

Golden, er, Tie Bar?

The summer months can be a slow time for modelling. In my case, some combination of being away from homes on weekends and inertia have combined to reduce progress of significance. While standing on the dock, waiting for the dog to bring the stick back and hide it in the woods, again, I formulated some goals.

First off was getting the rest of the turnout tie bars prepared (trimmed to length, glued together with insulating layer of paper, holes drilled out) and installed. I am pleased to report that goal has been achieved. Here is the last of four.

I did have to take out and redo one bar that was not, in fact, insulated. Happily, it was the first one I removed after I detected a short. New preparation step: test for short in the bar prior to installation! (Duh)

A positive aspect of the cut down straight pins I am using to fix points to bars is that they are easy to replace if, say, one slips out of the tweezers and goes shooting off to unknown parts.

A downside of a small layout constructed slowly is that you only get a skill up to speed and then you are done with it. I have worked out my process for doing tie bars but I will likely forget something by the time I need to do it again. Maybe I should write it all down or something. Next post!

 

A Good Iron Spike…

I have got all the rail down on Comstock Road. Wiring and point installation are pending as well as a lot of cosmetic tie plates and spikes but I am calling track laying complete.

Here is a status shot of the railroad for posterity.

If you squint, you will notice that the right leg of the turnout going off the front of the layout looks a bit odd. Since I don’t plan to launch any rolling stock into the ether, I have created a turnout with the frog removed. This is sometimes done to take a turnout out of service without abandoning or relaying track, just in case. In this instance, I laid the turnout as per normal and then pulled the frog and replaced it with a short piece of rail just as the prototype would have. I even put feeders under the dummy rails so I can restore things to operability if I ever want to.

I also cut the last rail spanning a baseboard joint which I had forgotten to do. I rechecked all the other rails since attempting to pull sections apart would be a bad way to discover another oversight. Getting the jewellers saw into position required some excavation of prematurely installed foamboard.

Four Closure Rails to Go

I am away from home this weekend so progress  actually on the layout is halted but before we set off, I managed to get everything but two sets of closure rails down on Comstock Road. This allowed me to push things through the other leg of the diamond to test things out. Putting down the closure rails require tweaking things so everything works so it is a non-trivial step but it is exciting to be able to see the “end” of track laying.

I anticipate getting the throw bars, linkages and servos installed on the remaining turnouts in the next couple of weeks.

It Ain’t Pretty But It Works

As the saying goes, it isn’t that a dancing bear dances well that is amazing but that it dances at all. I have got the diamond installed after much fiddling. It works but there were a few alignment issues with the frogs that make for imperfect lines through the crossing. I am impressed that my eye is less tolerant of variance than a finescale track standard. Anyway, I did not remake any parts but I will probably remake the whole thing at a future date. I will keep the functioning present version in order to get things running.

Here is a shot of the diamond from overhead.

And an artsy track level view.

Getting the challenging part of the trackplan inspired me to press on with the more mundane bits and now have the spur in front of the traverser tacked down as well. (I consider it installed enough for operational purposes when every third tie is spiked down.)

All the track laying remaining to be done is at least partially visible in this shot:

1. closure rails and points for the front track at centre back.
2. inactive turnout and spur off the upper right leg of the diamond.

That is a refreshing short list! After that, I am down to point servo installation and wiring before I can operate Comstock Road. Well, that and banging together enough rolling stock…

This Diamond Might Actually Work

Not installed or trimmed to length but I got the second k-crossing done tonight and just had to pose the two bits in situ on the layout. So far, things seem to be going well which probably means I have overlooked something. I am still half expecting to have to scrap and redo something but so far so good.

Freehand Rail Filing

Stephen Gardiner was kind enough to complement the quality of my incorrect filed angle and although I think he was just trying to make me feel better I did consider that perhaps describing my technique might be useful to someone. Having never done an instructional type of post, it will be a good exercise for me. All are encourage to ask questions if I have left something out!

So, you’ve got a piece of rail and you want to file the end to a particular angle.

I start by marking the angle on the top of the rail. I also sometimes mark the bottom as well or just the bottom depending on what seems necessary. If you are prone to getting an unwanted vertical angle as you file, do both so you can catch yourself at it. Machinists typically use a blue marking die which one either paints or sprays on. It is lacquer based so it smells and it takes a solvent to get it off again. For small jobs, I use a big Sharpie maker; an alternative I learned about in Simon Bolton’s books. The marker will do a 4″x10″ sheet of brass in less than a minute of vigorous scribbling if you need to.

I then use an engineer’s protractor to get the proper angle and a machinist’s scriber to make a mark in the blacked area on the rail.

The marker makes the scratch from the scriber easy to see.

After that, we get to the actual filing. I use a 12″ single cut file for most of my filing. This is less aggressive than default double cut file you get at the hardware store. You can usually find the single cut ones if you look. As far as actual technique, I grip the rail in my fingers and rub it back and forth on the file which I either lay on the bench or my lap. I find it easier to see and check the angle mark as opposed to clamping the rail and moving the file.

I check every dozen strokes or so to see how I am doing and adjust as necessary to try and keep the filing parallel to the mark on the rail. Eventually, I usually get down to the mark. If I mess it up, I either remark the end and take some more off or start on a new piece if I can’t spare any more length.