As part of my layout I would like to model the Redstone Bridge which is just a few miles down the tracks from me. http://johnmarvigbridges.org/Redstone%20Bridge.html
It's not the modeling of the bridge that is the concern (yet anyway), it is that I would like to animate it.
N scale, c55, NCE PowerCab. Or at least that is the plan.
I am leaning towards using Tam Valley Depot Singlet to control a servo. While that seems fairly straight forward in theory, I have one concern that I would like to address with another device.
I'm worried I will get side tracked and drive a train off into the river. I would like to add some sort of block detection to the singlet to assure that if a train is in that block the bridge will be in position for the train to cross. When the train is out of that block, the bridge will swing for "river traffic". No river traffic exists, but I think the animation of the bridge swinging would be a great effect.
Any ideas or concerns would be appreciated.
Chris
Easiest way I can think of is to use a Switchmaster stall motor to rotate the bridge. Put blocks in to stop the bridge when it's aligned with the track at one end of the swing and aligned with the river at the other. Control it with a DPDT toggle or a stationary decoder.
A micro switch can be used to cut the power on the tracks that lead up to the bridge. It won't help if the train is running in reverse though. A pair of signals on the approach tracks would be a nice detail.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
I guess what I was thinking more along the line of block detection or optic sensors that align the bridge when approched from either end. Completely eliminating the need for any switching on my part.
Circuitron makes so many different items to detect trains that I don't know where to begin to narrow my search down.
What ever companies detection I choose, it would need to sense the entire train length, so optical sensors seem to be what I need. Turn on when the loco is detected to align the bridge, and turn off when the caboose passes, turning the bridge 90 degrees for river traffic.
You don't really need block detection for this - more like some microswitches that get contacted when the bridge is completely closed. Power to the approach tracks on eityher side would go through this switch or switches. Then when the bridge is open, power is cut off so you can't run a train into the opening.
Additional contacts on the switches can operate simple red/green signals as well.
Keep it simple - no need to overcomplicate things, and it will be more reliable and less of a headache to build and maintain.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Chris,
I have Walthers Cornerstone HO scale double track swing bridge, working flawlessly for ten yrs. now. I agree with Randy...keep it simple. A forum member some time ago had trouble with not knowing how certain parts were assembled on the Walthers bridge so I drew out some tips right on the Walthers instructions. Pay attention on the diagram for wiring instructions, as to how the bridge opens and close's, You can disregard the Red marks. I run DC, so 8'' before the lip of the bridge on both sides, there is an isolated section controlled by a toggle switch, when power is killed from that section, a red signal comes on the search light type signal, Green when power is on...simple. All control is right near the bridge. Just remember...at all times the river bridge traffic has priority over Railroad traffic..Simple reason being, ships don't have brakes...
Take Care!
Frank
Living in the Chesapeake Bay region my whole life, we have lots of draw and swing bridges for both trains and highways.
In actual operation these bridges are always set to allow highway/rail traffic as the "normal" position, and only opened when ships need to pass.
Sheldon
That's really simple and cheap. It just depends on what block detection equipment you have.I assume this is the walthers swing bridge?
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
DigitalGriffin That's really simple and cheap. It just depends on what block detection equipment you have.I assume this is the walthers swing bridge?
I wish I could find a N Scale bridge kit. I am just going to use 3 Atlas c55 truss bridges and somehow make a swiveling center pillar for the middle one.
I am going to try the Tam Valley Singlet to operate the motion and going to try and mount a micro switch under the bridge to power up a dead rail on each side of the bridge. Should be a simple way to stop a train from going over the edge if the bridge is open for river traffic.
I haven't been to Radio Shack to see if they even make a micro switch small enough to fit under the bridge. Option 2 would be to rig the switch up under the layout and switched by the servo. Till I gather all the bits and pieces I really don't know what need to do to make it work.
If you operate trains in reverse (the push in push-pull) the dead section in advance of the bridge should be the full length of a normal train.
I ran into a similar problem, piling up a freight that backed into a turnout set for the opposite route. By the time the loco reached the stop section five cars were off the rails (and one was on the floor!) Now the stop section is as long as the longest train I'll ever run.
Then, too, the most spectacular crash on John Armstrong's Canandaigua Southern involved backing a train onto a bridge that hadn't been built yet.
Chuck (Modeling Central Japan in September, 1964)
tomikawaTT Then, too, the most spectacular crash on John Armstrong's Canandaigua Southern involved backing a train onto a bridge that hadn't been built yet. Chuck (Modeling Central Japan in September, 1964)
Even the biggest and best rail roads have accidents!
There "should" be enough space on both ends to be safe.
Thanks!
tomikawaTTThen, too, the most spectacular crash on John Armstrong's Canandaigua Southern involved backing a train onto a bridge that hadn't been built yet.
Now that.....took a lot of ''talent"!? LOL