Single point turnout

[bparrish]

So I mentioned in another thread that I am working on a trolley module railroad with another modeler in downtown Idaho.

I'm doing the turnouts and trolley poles for him.

This railroad is a point to point display layout with a loop at each end, taken from a 1954 issue of Model Railroader.

The concept is that the trolley will go around a loop and return to the other end.  In a brainstorming session over a few beers I thought that it would be cool if the trolley reversed its direction each time it went through the loop.  I decided that this could be done with no electrical components or switch machines.  When a railroad is on display the owner/operator does not want to be bothered with constantly operating something.  It is to run by itself and have bullet proof operation.

Below are three photos of the first of two turnouts that are to be identical. As this railroad will run from the trolley overhead wires the track work is all one side of the circuit.  He will be using EasyDCC for the control system

I had made seven of these turnouts for my own trolley railroad about 8 years ago but they are all on switch machines as mine is a operational railroad and not a operating display.

Single point turnouts were common in street railroads through the demise of trolleys in the 1950's  They only tolerated light equipment and low speeds so they were never seen on commercial mainline railroads.  In some cities they did in fact run some freight but nothing like the majors.

All of this is built on .020" circuit board and the rail is soldered directly to the board.  All of the copper will be covered with Plastruct sheet plastic that is impressed with a brick pattern and then painted.

The single point is visible in the photo and what makes it work is the sliding point grabs the inside of the flange and pulls the truck over into the turnout.  Trolleys routinely went through a lot of wheels as the back side of the wheel was regularly being worked.

The turned position and the straight positions are shown in the two photos.

The last photo shows the operational mechanism that allows this to work.  The wheels push the point so the point will remain in the same location upon return of the trolley and thus go the other way around the loop.  The spring loads the point down but the locked washers are necessary so that the spring cannot offer any return pressure to the point due to the spring winding up.  The double nut is necessary to lock the very light tension of the spring.


see ya
Bob

[deemery]

I'm not an expert by any means, but it's my vague recollection that spring switches were pretty common for streetcar/trolley prototypes.  In particular, they were used on passing sidings or gantlet tracks.


dave

[bparrish]

Dave...

You are correct about spring switches on street railways..... They allowed some reverse traffic and saved the motorman from getting down from the trolley.  In the early years 1900 -1920 many city railroads had a motorman and a conductor.  Later most companies went to only a motorman.  This really allow traffic to speed up.

I don't know how gauntlet tracks operated.

see ya
Bob

[bparrish]

Dave....

As I think about it more....... I don't think a gauntlet had any sliding points.  I think they operated with only a frog dedicated for each direction.  The two approaching tracks really did not commingle any one set of rails but were separate except for narrowing over a bridge.

see ya
Bob

[deemery]

I guess I'm thinking about a single track bridge with double-track approach.  Spring switches on each side make sure that the car entering the track on the left track exits the bridge onto the left track, and vise versa in the other direction.


dave

[jbvb]

How did you do the point - pivot rod joint?  The turnouts I've built on my layout and elsewhere use a 3/32" brass pivot rod silver-soldered to the base of the rail.

[bparrish]

James...

The sliding point is soft soldered over a 1/16th inch piece of steel alloy rod that takes solder very well.  It is out of the welding and brazing world.  That size rod threads very well to 1-72 threads.

Then I notch the base of the rail out so the rod is soldered on the side and end.  The rail head extends over the rod to make as continuous a nickel silver rail for the trolley as possible.

I'm making a second turnout in the next days so I'll put up a photo of the next one. I'm not sure I want to take the finished on apart again after having set the spring tension.

Thanx
Bob

[bparrish]

Here is a photo of the switch point.  The actual blade is about a half inch and the spring rod is .140" long with a 1-72 thread.  That thread choice is taken because of the 1/16th inch rod that I started with.

The blade is a small chunk of code 100 rail without much left ! ! !

see ya
Bob

[bparrish]

So here are the two turnouts done with the brick sheet set in. After mounting on the module these will be glued down.

Normally I would use plaster and carve in the brick but as a portable plaster is too brittle and subject to failing under vibration.

see ya
Bob

[donatode]

Neat.....and sharp!

[GPdemayo]

Well done Bob.....

[martin.ojaste]

Bob, those are some freakish points. Well done!!!

[bparrish]

Greg and Martin...

Thanx for your remarks and encouragement.

What makes these work is that the wheels get to the switch point first and it hauls the truck over to the turnout, or holds it straight.

There are not a lot of trolley modelers so this is pretty uncommon and fun stuff.

My test is to roll a rigid truck through turnout in all directions with only the weight of the truck.  If it works every time ... it's done.

These were easy because all the rail is the ground side.

These were turnouts 8 and 9.  I did seven about nine years ago so it took a little re-learning.

see ya
Bob

[ak-milw]

Nice ,neat work Bob.

[ACL1504]

Bob,

Great job, I likey(sic) very much.

See ya.

Tom