Aristo-Craft Manual Switch Machines
How to replace those finicky broken springs.
By: Keith Stratton

One thing all of us have in common in this hobby, at least those of us who have layouts, is the use of switches, or should I say turnouts…

There are many manufactures out there, but one who was around for a long time was Aristo-Craft and their switch machines were/are very popular. My layout has been in place for about 4 years now and all of my switches (41 in all) are Aristo-Craft with manual switch machines. For the first few years I was happy operating
the Creakin’ & Leakin’ GRR being blissfully unaware of what was about to start occurring. Last year one switch machine stopped working, then another, then another. Fortunately I had about 5 spare switch machines so I would simply change them out, that is, until I replaced the 5 th one…

You see, those pesky little springs inside had rusted and broken. I had a healthy collection of spare springs but had not yet taken one of the switch machines apart to see how on earth those springs could be replaced. Worse, I wanted to make sure I could get the darn thing back together again!

Some might say “Keith, why don’t you go with pneumatic switch machines, or remote electrically powered ones?” Well, for one I enjoy switching activities and if the real roads throw switches in yards then I will as well. Besides, we don’t get near enough exercise in this hobby… just sayin’.














                                       Picture #01                                                                                                  Picture #02

So, I had a handful of these of these ‘out of service’ switch machines, as  shown on the left hand side of picture #01 with a ‘Broken Spring’ tag. Time to dig in. First thing you need to do is to remove the screw holding the throw lever in place. Remove the screw and gently pull straight up on the throw lever as it sits on a  square end of the rotary actuator shaft. Now flip the switch machine over and remove the three screws holding the two halves of the switch machine together. They fit together quite snugly so you might want to get a small flat screwdriver and gently pry the two halves apart.

Once apart it will be apparent what the problem is. The spring usually rusts through right by the connection point on the rotary actuator shaft. You will be surprised at how much dirt etc. collects inside the enclosure, see Picture #02, so get an old toothbrush and head to the sink to give everything a real good clean.















                                                     Picture #03

                                                                                                                                                                                 Picture #04
Picture #03 shows all of the parts and from left to right, and they are: Throw Lever, Housing, Base Plate, Throw Bar, Intermediate Throw Bar and Rotary Actuator Shaft. I have no idea if this is what they are actually called, but in this article that’s what I call them (I forgot to include the spring, but there are plenty of pictures of it as
fitted). Getting the spring end connection onto the mounting tab of the rotary actuator shaft is a bit tricky but with perseverance you’ll get it on… really! One tip is to set the rotary actuator upside down on top of the top side of the housing to hold it in place while you fit the spring onto the mounting tab, as shown in Picture #04.













                                          Picture #05                                                                                                   Picture #06

Pictures #05 and #06 shows the spring connected to the intermediate throw bar. On the left side of the picture and in the right side of the picture the intermediate throw bar has been fitted back onto the lower side of the rotary actuator shaft. Picture #05 is looking from the top while Picture #06 is looking from the bottom.
















                                          Picture #07                                                                                                   Picture #08

The throw bar has been placed in the base plate in Picture #07. Next, place the rotary actuator/ spring/ intermediate throw bar assembly in place in the base plate ensuring the square end of the shaft is facing up. Engage the hole in the intermediate throw bar with the pin on the throw bar and then, while holding down
on the rotary actuator shaft, rotate the shaft to the left and right and observe how the switch machine functions. Pictures #08 and #09 show the throw bar in both positions.


















                                              Picture #09



                                                                                                                                                                        Picture #10
You will notice that the tab on the rotary actuator bar will sit outside of the base plate (in either position) and it will need to be centered in order to install the housing. You will see in Picture #10 where I have inserted a very narrow chisel into the screw hole and have twisted it to center the tab of the rotary actuator shaft (for illustrative purposes only). Picture #11 shows the chisel inserted through the shaft opening in the housing, with the tab in the center position. The housing can now be lowered into place. Sometimes the throw bar will need to be wiggled a bit before the housing fully mates onto the base plate.






















                                                                                                          Picture #11
                                                                                                     
Once you have done a couple of these it should only take about 10 minutes to change out a spring and put your super clean switch machine back in service for another few years.

Over time I will likely convert all of my switch machines to tenmille throws, but in the meantime I’ll use the Aristo-Craft switch machines until I run out of parts!
I hope you have found this information helpful, even if you don’t run Aristo Craft
switches!