Monday, May 9, 2011

Bullfrog Mechanical Turnout Controls Are A Go!

Track is down. Woo hoo! Super-
detailing, here I come!
With tracklaying more or less complete, I turned this past weekend to turnout controls. As I mentioned in my previous post, turnout control is among my least favorite model railroad tasks.

Why the hate, you ask? Some of my earliest memories of model railroading include the realization that Atlas and Tyco snap-track turnout motors are horrifically unrealistic, and a frustratingly precise touch of the button was needed to get those solenoid-powered things to actually fire.

The previous Dunes Junction layout used Fulgurex worm-gear motors and a home brewed linkage doodad that I cooked up with brass wire and tubing and some Rube Goldberg-style good luck.  The Fulgurexes were not all that tricky, but expensive and noisy. My linkages were downright hideous, too.

In my quest for a happier, simpler Dunes Junction, I thought I'd go for a more elegant solution than grinding old turnout motors and DPDT control switches. I'd always liked the idea of throwing turnouts via a trackside mechanical throw, but that's impractical over track that will eventually sport a delicate lace of catenary wire.  Thus, I needed a turnout control that is under the table and elminates the need to reach across the tracks.  That's where mechanical turnout control comes in.

In the days of yore, some model railroaders used choke cables from the automotive world to control turnouts, instead of solenoids or motors and worm gears. The modern iteration of  mechanical turnout control uses radio control airplane control rods, and a kind of mechanical-only, non-electrical locking mechanism such as FastTracks' Bullfrog or New Rail Models' Blue Point controllers. There are some homebuilt ways of doing mechanical turnout control as well, usually using an electrical switch or a door latch as a locking mechanism.

FastTracks Bullfrog awaiting assembly. Did I mention
these are extremely fun to assemble?
I ordered Bullfrog crossover controller kits from FastTracks for the Dunes Junction.  Nice, responsive, and personal service--hey, they're Canadians, so politeness and civility are the order of the day.  This also means that they ship via CanadaPost and the package clears customs, blah, blah, blah--not good if you are in a hurry. Having made two separate orders from FastTracks, I recommend paying slightly more for air service--it makes a huge difference in delivery time

BullFrogs and Tadpoles assembled and ready
for installation. That SpongeBob mechanical pencil
adds visual interest to my workbench.
These little gems are laser-cut from sheet wood. Wood or white glue secures the super-precise joints; a spring and ball bearing nestles into a circle shaped pocket for locking action.  The only tool necessary is sandpaper--I used a coarse manicure/pedicure board from a beauty supply store.

Piano wire provides a springy but firm linkage to the turnout throw bar.  Nesting plastic tubes typically used in radio control aircraft provide the mechanical control rod linkage from layout edge or control panel to the controller. These control rods need be mounted and guided firmly, so the crossover kits also come with Tadpole mounts, which are also laser-cut wood.

BullFrog with z-link for
crossover control. That black thing
is an SPDT microswitch, which can
be used to power turnout frogs.
Mounting and adjusting the BullFrogs is somewhat painstaking. I had predrilled 3/8" holes under my turnout throwbars in preparation for tracklaying, and the linkage rods fit neatly into the existing holes in the Peco turnout throwbars. #6 screws secured the BullFrogs; slotted mounting holes allow for lateral adjustment. Make sure the BullFrog motion is square against the throwbar and focus the tension of rod on the side-to-side movement of the throwbar--avoid having the rod apply pressure in the direction parallel to the rails.

Control nobs, front of layout view
I mounted the control rods and knobs to the layout edge first, and got them to work. Then I laid the long runs of rod that linked the two crossover turnouts.

My #8 crossovers turned out to be too long for the rod material provided with the crossover kits, but I found that Sullivan Gold-n-Rod control rod kits in the radio control department of my local hobby shop are an exact match for the FastTracks rods. The Sullivan kits also include hardware such as clevises and couplings that came in handy during installation.

Control knob from rear/underneath
One key lesson I learned is that the rod runs should be kept as naturally curving and an simple as possible, with only a minimum of vertical and horizontal curves.  Duct tape also helps to keep play out of the rods, so that the mechanical motion is focused on moving the turnouts instead of wiggling the rods.
 The brass Sullivan clevis is clearlyvisible, as is some duct tape that
steadies the control rod.

The brass clevises provided in the Sullivan Gold-n-Rod kit turned out to be a lifesaver--instead of trying to thread the z-bend rod ends provided by FastTracks into the BullFrogs after they had been mounted and adjusted into the layout, I was able to screw the clevises into the rod ends and simply snap them on to the BullFrogs.

BullFrog control rod overview. Look, no turnout control wires or switches!

Overall, I am quite happy with my BullFrog turnout controls.  To operate, they require a satisfying but firm pull, and lock into place with an understated click. And no wiring of switch machines and toggles! Woo hoo!

Next up: feed wires, then track detailing.