Switch Machine Fitting

Fitting the Atlas O switch machine to Ross Custom Switches

Ross Custom Switches can be had with DZ1000 or DZ2500 switch machines pre-installed. These are great switch machines, but the DZ1000 has no passive non-derailing and the DZ2500 also has no unpowered operaton. I tend to be a runner who simplifies in the face of adversity (that is, "if it ain't broke, don't fix it; and if it is broke, make do without it." While I have set up most of my switches with TMCC operation, the electrical side of things fails sometimes. When installing or relocating track and switches, I prefer to not hassle with this level of complexity at all.

Ross O31-O54 in Yard

This switch has been in place for several years with no switch machine or even a switch throw. It's been operated manually, the points allowed to sway in the breeze. Up til now.

Placing the Machine

Works better on the outside, but I want easy access to the manual slide. And I don't want to cut up the scenery, or deal with clearance for the grade track in the background.

Pry open the business end first

I sort of wedge my fingertips in between the upper and lower flaps, to create a slight separating pressure as I hold the end with my right hand. I keep my RH fingertip braced on the base to keep from driving the screwdriver in too far when I push the tab clip in.

And, voila! It's separated. Can't let pull up yet, til the other end tab is open; can't let go, or it'll reseat and re-clip itself.

Pry up other end tab

The end will quickly separate as soon as the second tab clip is released.

First side tab

If you have fingernails, this is a great time to use them. Be extra-careful pushing in these side tabs: there isn't much to keep you from driving the screwdriver into the wire coil inside.

Pry open end tab

Same as above.

Now for the other side

One side clip, one end clip.

Lift off top cover

The hook tab on the coil end allows you to pull up the throw end first. Once it's open, you'll see the throwbar assembly (in my left hand, on your right in the picture above) just sits loose on the switch slider (the brown plastic plate with a zig-zag slot, to your left in the picture above).

Putting the cover back on, hook that back edge under first, then work your way up the tabs in pairs. You'll have to press the tab pairs in toward each other as you go. You'll also need to do this without disturbing the throwbar assembly. This is a good time to practice putting the cover on without disturbing the throwbar assembly. Besides, maybe the hobby shop is still open, in case you break off 2 of those plastic tabs! :)

Clip off the side braces

I think these are to clip the switch into Atlas switches. We don't need them. The plastic is hard and brittle; you can get these off cleaner with a zona saw, which I use if trimming off the end tabs or the thicker side-screw-tabs. But for these 8 tabs I like to just clip 'em off.

Pull the pin off the Spring

This spring in its default 3rd-hole position has too much tension for the passive non-derailing action on cars under 16 oz. Later we'll put it back in on the 2nd hole.

Clean off excess flash

There's a tiny bit of flash on the pivot point under this assembly. No enough to bother with. The flash on the inside face, partly obscured by the brace in this shot, is not bad but I'd trim it anyway. I've had 1 switch where this flash was enough to mess up the spring.

Trim the guides if needed

This is not really a beginner's move, but for the O31-O54 with the switch machine mounted on the inside, it helps. The switch machine is not at a 90-degree angle to the switch's points; this means that the passive non-derailing slide is easy pulling the points away from the machine, and harder pushing toward the machine. By shaving the "away" side of the guides, I make a gentler slope and make up for some of that discrepancy.

Guides trimmed

A pretty crude job, but effective. In this photo you can also see the spring pin in the second hole.

Before you add the spring back in, dust or vacuum to keep all debris out of the workings. Empty you vacuum before you start, that will make it easier to find the pin when you accidentally vacuum it up! :)

Put the spring back on its pin

Super-skinny needle nose pliers are good for this.

Hooking the spring onto the pin

I keep my thumb poised to push the pin into place as soon as the spring loop is there.

Locate the machine for scribing

I pushed the coil end right up to the inside rail; on the points end you want 1/8" clearance between the black plastic bar of the switch and the brown base tab of the switch machine.

Scribing left

Like I said, right up on the rails. This is prototypical, ain't it? :) Good thing this end of the machine will be on the cork roadbed: if you leave it up on the ties, some trains will clip the corner.

Scribing right

I try to cheat the cut in slightly, to ensure there is a little adjustment room after all is in place.

Scribing end

Yes I know it's simpler to just cut the end off. I like the nice snug fit, what can I say?

Cut the ties

I like the dremel wood-saw setup. Higher RPM than I'd like, but I haven't maimed myself yet.

Another cut

Scribe lines are clearly visible in this shot.

Cut for tabs

Wedging the switch machine's end tabs under the ties might be do-able, but often results in deforming pressure that makes the switch's operation less smooth.

Pocket cuts & finishing corners

I switch to a long burr bit to get where the wood saw can't reach.

Cleaning the corner

With practice, you'll learn to gauge how deep is just deep enough to cut the ties and leave the roadbed.

Cleaning under the ties

Note the end tab only goes about this far, no need to chase this slot all the way back to the rail.

Cleaning the other end

It's just a sliver of wood, but still enough to bind the switch if you just force the switch machine's end tab under without the slot.

Vacuum everything

Remember that every bit of dust and debris can get into your switch points, machine, loco, and wheels.

Test fit

It helps to test fit fairly often but don't over do it: you're working with an open switch machine.

Nice gap!

I was so pleased with myself on the first couple machines, with the perfect cuts and the machine snugged in just right. Then I hit one where the fit was perfect but I needed another 1/2 mm to get the points just right. I chose to go in with the burr tool, and it took out almost 2mm... 3 times what I would have needed if I'd just built in the gap to begin with.

Test fit under tie

I had to carve this one out a bit after the test fit. It went in. but was a tad too tight.

There, that's better!

And we're not even up aginst the rail... tons of room! :)

Now for the hard part

The Ross Pin ships with every Atlas O switch machine. It will clip onto the black-plastic points bar on the Ross switch. It doesn't go on easy... which is good, because that means it won't come off easy either.

Back-brace the points bar

I push the points most of the way toward the switch machine, then put in a strong screw behind the bar to act as a backstop. This way, the pushing pressure on the points bar is transferred to the screw, not to the points. Note that the screw is a backstop: it is not actually touching the points bar when screwed in.

Pry open the Ross Bar

Take the time to find just the right tool for prying open the ross bar. Here I'm using the screwdriver I used for popping the switch machine cover off, rotating counterclockwise to open the jaws. Its tip is 7/64" wide. 3/32" would be better; 1/8" would probably be too much.

Slide into place

Holding the screwdriver in the jaws-opened rotation, I work the jaws over the points bar. It still takes a bit of force to get onto the points bar: tht's what the backstop screw is in place for. Don't worry about getting the jaws all the way to their hole in the points bar, just get 'em onto the bar for now.

Take out the screwdriver

If the crewdriver hasn't fallen out of your hands on its own as you got the jaws onto the points bar, un-rotate it and take it away. Once the jaws are on the points bar and the screwdriver is out of the way, it's easy to slide the jaws around to find their hole.

Check the action

Slide the points open & closed. Make sure the action is smooth and nothing is binding. Fixing it now might be a pain but it's easier than fixing it later.

Load the switch machine's throwbar

I use a straight pin to fish out the spring end and to hold it out in place. Take care to try a couple directions on the fishing-out: you want the spring's end loop to be as close to "flat" as possible.

Vacuum everything

This is actually probably the 4th time I've vacuumed since the last time I showed it.

Loop the Ross bar onto the spring

It's good to get the switch slider plate and the throwbar assembly lined up with the pin for this operation, but it's hooking the pin that is important here. It may take a few tries.

Hooking the pin close-up

I tried to get a good close-up of this. It's not hard once you know what you're doing, but it's kind of a 3-hands operation.

Finished setup

After you get the pin hooked, make sure you got the throwbar assembly seated in its pivot hole (under the spring pin) and in the switch slider (zig-zag slot visible in this shot).

Is that a piece of ground foam in there? I guess it's time to vacuum again...

Vauum again

This time I'll hold down the moving parts.

Re-assemble the cover

Hooking the back clip...

Cover side clips

This is where your practice pays off. It'd be a shame to disturb the throwbar assembly at this point.

Second side clips

You can see by the white on my fingers that I'm squeezing to get those clips in a little. This makes them snap down smooth with less disturbance to the business end of the switch machine.

Test the action and ajust final position

I weight a car to my preferred light load (this ore car is weighted to 10.5 oz) and use a stick to pull the car through the switch. You can also roll a consist through, to better simulate the action. Do this over and over, pushing & pulling the switch machine in tiny increments in all directions until you find the ideal spot. Decide also which way you want to "cheat" the points. I cheated toward the outside a little. That means when the train is going into the points and the points are on the outside rail, it will have slightly more tension than when the points are on the inside rail. Since the outside-rail position has a milder curve (and due to the skew of the switch machine), the non-derailing "push" is easier for the cars in that position. So cheating toward the oustide by a gram or two makes the best balance on the passive non-derailing action.

Screw down the end tab

I use a #4 screw and a washer so that there is some room for the tab to move in case I need a fine-tuning adjustment sometime later on.

Drill for the other end tab

If your end tab is under a tie, just use the tie as a "washer" by drilling through it.

Screw down the other end

And there you have it! Eventually I will hook up wires to this and my other Atlas O switches. But for now, I'm mostly just happy to have the switches in place, and their passive non-derailing is working great on every one of them!

Other Examples

This was my 5th Atlas O switch machine I should have started with a simpler one to use as a starting example. I'll add those later.

Wiring the Switch

I'll write about that when I get around to doing it. Atlas O has a new switch controller coming out, I'll be using one on each switch.

Credits

NPF Railway

Northern Pacific Freelance model railroading