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Idea for making a custom N Scale bascule bridge. Thoughts?

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Idea for making a custom N Scale bascule bridge. Thoughts?
Posted by CTConrail on Friday, October 19, 2018 3:27 PM

So if you are an N scaler like me you may know that we have a lack of lift and bascule bridges in our scale aside from a couple expensive custom non operating models that are out there. Yes I can make a go at scratchbuilding one after the myriad of other scratch build projects that are on my to do list but I accidently stumbled upon this and ordered one. Its a great starting point however it needs some minor modification to properly work with an scale. I will also need to add some sort of motor to it . The link is below for the bridge. Its 1:130 scale and made from thick balsa wood. Let me know what you all think and if you have any ideas on how to make it motorized or anything else that may help bring life and realism to it. Thanks guys.

lift bridge kit

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Posted by hon30critter on Friday, October 19, 2018 9:40 PM

Hi CTConrail,

The bridge kit looks really interesting. I wonder if you could power it with a Tortoise located under the roadbed approaching the bridge? If the bridge is balanced properly it wouldn't take much force to lift it, and if you are using it as a working rail bridge the Tortoise action would hold the bridge down firmly enough to keep it from bouncing.

I would buy the kit just for the design. If the actual kit is too heavy looking you could use it as a pattern to build a styrene version.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by ROBERT PETRICK on Friday, October 19, 2018 10:30 PM

Hey CTC-

I also model N scale, so I know how you feel about the lack of non-ordinary buildings and structures.

In a previous life, I built tall ships (wooden sailing ships) from commercial kits and Midwest was one manufacturer of such kits. Pretty decent. Not the highest, most exclusive line; but nothing to sneeze at either.

The kit you're looking at appears to be laser cut from plywood. The detail doesn't seem to be too great, but you can probably rest assured that the pieces and parts fit together.

Dave's idea about rigging up a Tortoise motor sounds doable. And for that matter, rigging up a Tortoise to one of those higher-end more-detailed static models also sounds doable.

At any rate . . . maybe you could give it a try.

Good luck. Let us know how things turn out. 

Robert

LINK to SNSR Blog


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Posted by 7j43k on Saturday, October 20, 2018 10:11 AM

I like that bridge a lot.  And the price is right.  It's not a railroad bridge, but a road bridge.

It reminds me of bridges across the Chicago River.  I recommend you use two, touching nose to nose.  And paint and "weather" them nicely (there is NO detailing on them).  Especially in the background, they'll look very nice.  And motorized, they'll be an eyecatcher.

I am wary of assuming a Tortoise will work.  I think you won't get enough movement.  I think it will need a real motor(s).  I've seen this kind of bridge powered by a motor that runs a string along the structure of the bridge.  I recommend you wait until you have the bridge on hand before getting serious.

 

 

 

If you want a RAILROAD bridge, and you're willing to accept a vertical lift bridge instead of a Bascule (in this case, a Scherzer), I'd start with something like this Central Valley bridge:

 

 

You'll have the actual bridge "taken care of".  Just add towers and some distinctive detailing (see the current topic on an HO vertical lift bridge).

 

Ed

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Posted by CTConrail on Saturday, October 20, 2018 10:56 AM

BridgeEd I actually was going to use a bridge like that as a starting point for a vertical and still may. I already got this midwest bridge, modified it to make it a level bed and built it. It has no detail but I can fix that and then paint and weather it. This image is just the starting point. I will definitely give it life and more realism.

What exactly is a tortoise motor you guys spoke of? Have any info on them? It doesn't take much to lift this however track will add more weight. I ordered another but i am going to build a prototype for myself and sell the other when complete. I'm sure ill have no lack of buyers if done right. I will need to add some sort of timer to stop the motor when at the highest point on lift and same thing when its down. I need to figure out how I'm going to do the electronics.

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Posted by richhotrain on Saturday, October 20, 2018 11:12 AM

A Tortoise is an elctronic geared device to throw point rails on a turnout. It probably does not provide enough lateral movement to lift such a bridge.

Rich

Alton Junction

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Posted by 7j43k on Saturday, October 20, 2018 11:26 AM

CTConrail

BridgeEd I actually was going to use a bridge like that as a starting point for a vertical and still may. I already got this midwest bridge, modified it to make it a level bed and built it. It has no detail but I can fix that and then paint and weather it. This image is just the starting point. I will definitely give it life and more realism.

I just discovered that the company that makes Frank's HO lift bridge also makes them in N, both double and single track:

http://www.custommodelrailroads.com/VLB-ST-N.aspx

They also make a Scherzer (Bascule) in HO.  You could write them and see what their thoughts are about doing an N version.  My GUESS is that it's a PITA, or they'd already offer it.  But I'd still write, anyway.

What exactly is a tortoise motor you guys spoke of? Have any info on them? It doesn't take much to lift this however track will add more weight. I ordered another but i am going to build a prototype for myself and sell the other when complete. I'm sure ill have no lack of buyers if done right. I will need to add some sort of timer to stop the motor when at the highest point on lift and same thing when its down. I need to figure out how I'm going to do the electronics.

 

 

No to the timer.  You'll need two limit switches (open and closed).  The wiring should be very simple, though I'll depend on someone else to lay it out.  They COULD (SHOULD) be under the table, with the bridge rolling over an upwards projecting rod to throw the switches.  Much better than mounting the switches out on the structure.

You'll want the bridge to be as heavy as possible, so as to reliably push the rods down.  AND you'll want to do a good job of counterbalancing it.  To ease the load on the motor and its linkages.  And to push the rods down even better.

 

Ed

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Posted by zstripe on Saturday, October 20, 2018 11:37 AM

You would need two normally open Micro Switches, to raise stop/to lower stop....wiring similar to the diagram in the photo. It is from the Walthers working swing bridge that I have on My layout. A forum member had a problem with His and I used the diagram to try and help Him out a few yrs.ago.

A photo of the bridge when I first started working on the scene:

Take Care! Big Smile

Frank

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Posted by ROBERT PETRICK on Saturday, October 20, 2018 12:20 PM

richhotrain

A Tortoise is an elctronic geared device to throw point rails on a turnout. It probably does not provide enough lateral movement to lift such a bridge.

Rich

Yeah, maybe. But if you use a stiffer lever than the thin wire supplied and move the fulcrum a little, I think you could raise and lower the bascule leaves their full sweep.

Robert

LINK to SNSR Blog


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Posted by richhotrain on Saturday, October 20, 2018 3:33 PM

ROBERT PETRICK
 
richhotrain

A Tortoise is an elctronic geared device to throw point rails on a turnout. It probably does not provide enough lateral movement to lift such a bridge.

Rich 

Yeah, maybe. But if you use a stiffer lever than the thin wire supplied and move the fulcrum a little, I think you could raise and lower the bascule leaves their full sweep.

Robert 

Maybe.

Rich

Alton Junction

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Posted by richhotrain on Saturday, October 20, 2018 3:38 PM

Regarding CMR, by all means email them about the possibility of an N scale Scherzer bascule bridge. They are highly responsive to emails.

Since the vertical lift bridge is already available in both HO scale and N scale, I see no reason not to make the Scherzer bascule bridge in N scale.

Rich

Alton Junction

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Posted by CTConrail on Saturday, October 20, 2018 3:45 PM

I just discovered that the company that makes Frank's HO lift bridge also makes them in N, both double and single track:

http://www.custommodelrailroads.com/VLB-ST-N.aspx

They also make a Scherzer (Bascule) in HO.  You could write them and see what their thoughts are about doing an N version.  My GUESS is that it's a PITA, or they'd already offer it.  But I'd still write, anyway.

 

I have seen those. They make a lot of nice structures but that bridge (the vertical) is static I believe. I would rather build my own working vertical lift bridge. Their HO bascule is nice! I could email them and see if they have any plans for N.

As far as my bascule goes i guess micro switches it is.  I will find a slow geared 12v motor and a spdt relay for lift and lower. I think it will turn out nice. Have a few ideas for detailing it. If anyone else has any ideas that may help let me know. Once I finish these bridges I will start on a vertical lift. I'll keep this post alive with photos and updates on this bridge though.

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Posted by zstripe on Saturday, October 20, 2018 6:14 PM

You would be better off with a DPDT center off switch. The motor I am using is a 320:1 gear ratio and although it is a 12vdc motor, I'm running it on 6vdc for a almost perfect speed........12vdc is way too fast.

Good Luck! Big Smile

Frank

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Posted by richhotrain on Sunday, October 21, 2018 4:30 AM

I admire anyone who successfully automates a lift bridge or bascule bridge to actually operate. I have two of Walthers bascule bridges, but neither is operational for several reasons.

First, the Walthers bascule bridge does not easily lend itself to automation. The parts provided do not work properly. So, you need to be a mechancial engineer to design your own system of moveable parts.

Second, operating bridges add too much complexity to the track work. I struggle enough when layiing track to get it straight and derailment free. I can only imagine the problems with track alignment on an operating bridge.

Third, an operating bridge looks cool but simply takes away from the operation of trains which have to stop and wait for the bridge to rise. Yeah, I know, that's what happens on the prototype, but operating bridges seem a little too toylike to me. And, don't ask me why I have an operating turntable on my layout. LOL

Rich

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Posted by hon30critter on Sunday, October 21, 2018 6:23 AM

CTConrail
What exactly is a tortoise motor you guys spoke of? Have any info on them?

Here is what a Tortoise looks like:

http://www.circuitron.com/index_files/Tortoise.htm

The Tortoise is a 'stall' motor type of device. In other words there is always power supplied to the motor and the motor simply stalls when it reaches the end of its' travel. The amount of power used is minimal so the stalling doesn't cause any problems. The advantage for you is that the stalled Tortoise will exert constant force on the bridge so it will hold the bridge down when closed. The amount of force will vary depending on how long the lever rod is and where the fulcrum is placed, but I'm guessing that it might be enough to keep the bridge from bouncing as traffic went over it.

Simply put, it pushes a rod slowly back and forth to mimic the normal operation of a switch machine. The Tortoise can be mounted remotely with a home made linkage connecting the rod to whatever you want to move, in your case the bridge.

Ed raises a valid concern about whether or not the maximum distance of the Tortoise throw would be far enough to get the bridge fully open and closed. The throw can be adjusted by moving the fulcrum, and the length of the throw rod can be increased (within reason) to allow for more throw.

As to how much force is required to lift the bridge, I think there should be very little. If the bridge is balanced properly it should pivot back and forth very easily. If it does swing easily the attachement point for the actuating lever could be positioned closer to the pivot shaft to increase the travel of the bridge. It wouldn't hurt to build in some brass or nylon bushings so that things move freely and have as little play as possible. You might have to fake the gear engagement if you can't get the gear racks to move easily.

My 2 Cents

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by CTConrail on Sunday, October 21, 2018 8:09 AM

So basically tortoise motors are used in place of the ugly black surface mounted switch motors that turnouts come with? I don't know how i would use one of those on this application though. I had an idea that is actually how the HO bascule from Custom Model Railroads is set up. Small motor and strings to lift and lower like cables almost.

Frank do you have a link for the motor you useda and are you using an attenuator to drop the voltage down?

Rich I hear what you are saying but I think it adds more realism and if it operates slowly like the real thing I don't think it will be toylike. Gives a little more of a challenge when operating multiple trains also which is cool with me. Will go perfectly somewhere near my container port area.

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Posted by zstripe on Sunday, October 21, 2018 9:14 AM

I used the Walthers motor. It did not come with the kit. It had to be purchased separately. But the motor was designed for a lot of their models. Mine was a little cheaper back then in the early 90's. I got the Bascule bridge first, which I did get to work properly, after a lot of trial and error. I found that the arms with the cog rail in them had to be exactly the same on both sides, (gears lined up) with the drive gears connected to the motor shaft, had to fit in the cog rail rail also exactly the same on both sides, otherwise it would bind enough to stop it from working. I tested mine without the counterweight on it and it worked perfectly so I did not need to add a lot of weight. It will be going on My Grandson's layout. Mine is all double track mainline and I had no place for it. That's why I got the swing bridge.

The Vertical bridge I am working on now, will need two (2) motors, one on each tower. I'm not going to power mine right now, but I made provision to do so at a later date. I will need two N-scale engine motors with flywheels. The flywheels will have to be machined on a lathe to make three v-groves in each one. Using wood ship building rigging twine for the cables, all six cables on each side being the same length. The motors would have to run in opposite polarityto raise and lower. The tracks for the bridge to slide on are easily made from brass channel. My kit came with a full sheet of the hoist platform parts as an extra.....so I can play around with that and still have the bridge on the layout. I will not be glueing the hoist platforms I made on.....there really is no need, they fit tight and perfect.

I also noticed that Walthers changed the gear ratio on the motor, mine says 320:1, new one states 360:1

https://www.walthers.com/motorizing-kit-fits-swing-bridge-oil-pumps-turntable-other-kits

I have some links to some other animation type motors if interested.

Good Luck! Big Smile

Frank

 

 

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Posted by CTConrail on Sunday, October 21, 2018 11:14 AM

zstripe

I used the Walthers motor. It did not come with the kit. It had to be purchased separately. But the motor was designed for a lot of their models. Mine was a little cheaper back then in the early 90's. I got the Bascule bridge first, which I did get to work properly, after a lot of trial and error. I found that the arms with the cog rail in them had to be exactly the same on both sides, (gears lined up) with the drive gears connected to the motor shaft, had to fit in the cog rail rail also exactly the same on both sides, otherwise it would bind enough to stop it from working. I tested mine without the counterweight on it and it worked perfectly so I did not need to add a lot of weight. It will be going on My Grandson's layout. Mine is all double track mainline and I had no place for it. That's why I got the swing bridge.

The Vertical bridge I am working on now, will need two (2) motors, one on each tower. I'm not going to power mine right now, but I made provision to do so at a later date. I will need two N-scale engine motors with flywheels. The flywheels will have to be machined on a lathe to make three v-groves in each one. Using wood ship building rigging twine for the cables, all six cables on each side being the same length. The motors would have to run in opposite polarityto raise and lower. The tracks for the bridge to slide on are easily made from brass channel. My kit came with a full sheet of the hoist platform parts as an extra.....so I can play around with that and still have the bridge on the layout. I will not be glueing the hoist platforms I made on.....there really is no need, they fit tight and perfect.

I also noticed that Walthers changed the gear ratio on the motor, mine says 320:1, new one states 360:1

https://www.walthers.com/motorizing-kit-fits-swing-bridge-oil-pumps-turntable-other-kits

I have some links to some other animation type motors if interested.

Good Luck! Big Smile

Frank

 

 

 

Does that Walthers motor come with the other gears for the motor to engage with or are they already on the models that the motor is made for? Sure any links you have would be great. Thanks!

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Posted by zstripe on Sunday, October 21, 2018 1:09 PM

The swing bridge came with all the parts necessary to power it, just lacking the motor. The Bascule bridge also came with the gears/parts to power it, along with a horizontal shaft motor. The system they came up with to start/stop it, were really useless in MHO. I just used a DPDT center off toggle to control it. Here are a couple links to Motors/Gearing and a whole bunch of other goodies, full range servos, etc. I have purchased from both places a number of times, for many other projects not even related to Model Railroad........ I build and work on RC vehicles also, which My younger Son and His Son's spend a lot of their time on.

The Links:

Gears/gearing:

https://www.ebay.com/p/75-Type-Plastic-Crown-Gear-Single-Double-Reduction-Worm-Small-Parts-Wheel-up/1342953375?_trkparms=aid%3D333200%26algo%3DCOMP.MBE%26ao%3D1%26asc%3D20170706093515%26meid%3Dba6fc16a1f7d4824a6c867b6283c71bb%26pid%3D100831%26rk%3D2%26rkt%3D3%26%26itm%3D163012479999&_trksid=p2349526.c100831.m5025&iid=163012479999

Motors, etc.

https://www.allelectronics.com/category/400/motors/1.html

Good Luck! Big Smile

Frank

Edit: BTW, I was going to include this in My post, but I forgot. In Your case with the smaller bridge, instead of a motor, browse through that link and look for 360 degree rotation servo's. I believe that may work better in Your application.

 

 

 

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Posted by CTConrail on Sunday, October 21, 2018 4:12 PM

zstripe

 

Edit: BTW, I was going to include this in My post, but I forgot. In Your case with the smaller bridge, instead of a motor, browse through that link and look for 360 degree rotation servo's. I believe that may work better in Your application.

 

Thanks for the info Frank. I took a browse through the motors and the 360 servo and am trying to figure out which one and how and where I will place it to operate it. Should be pretty easy if I use strings like the CMR bridge. Not sure if that's the route I will go or not yet though.

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