1/8 Scale is 1.5 inch to the foot. The track gauge should be, and is on the East side of the U.S., 7.25”. However, in the West, it’s 7.5”, although many today are built at 7-5/8”. Being large enough to ride on, but small enough to haul around, it’s the HO (most popular) of large scale.
This scale is rarely (I’ve not seen one) used as a commercial amusement park type ride. Because the gauge, and rolling stock, is so small, it is a bit unstable with full size humans on them, unless they stay still, stay centered, or have experience riding them.
Most 1/8 scale railroads are privately owned, but there are 1/8 Scale clubs around. Most of the clubs offer rides to the public, but they don’t charge for it. Instead, they usually have a donation box. And, they have strict rules in an effort to avoid accidents—many of which stem from the rider twisting and/or leaning over, causing the car to tip over.
Some of the privately owned railroads offer rides to the public, but most are not open to the public because of lawsuits stemming from the accidents described above. In fact, I know of a railroad that was lost in a lawsuit due to an accident caused by the plaintiff. A lady panicked when the train went over a trestle, and caused the train to derail and turn over. She sued and won. The cost: the land that the railroad was on.
I’ve enjoyed going to various 1/8 Scale railroad for years—since about 1995. My two favorites are Train Mountain in Chiliquin Oregon, and Bitter Creek Western just outside Arroyo Grande, CA, about halfway between Los Angeles and San Francisco along Highway 101.
One of the first things I did after retiring was buy an 1/8 scale GP40. It was not in running condition, but had what I wanted; being battery powered. It uses a 50 amp golf cart motor, powered by three deep cycle 12V car type batteries. It came with a golf cart controller, but did not work because its mechanical reversing unit was wired wrong. Had it been wired correctly, it may have run. But I didn’t figure that out until I had all the schematics drawn while disassembling it, and testing to figure out how it should be.
No matter though. My goal is to use DCC to control it and I now have schematics drawn for it to use DCC control.
Train Control Systems is getting the parts for me, and testing them, to build a powerful H-Bridge to power the 50 amp motor using a decoder’s output for control. With this, I will have the same programmability with this engine as I have with an HO-Scale engine; Vstart, Vmid, Vmax, momentum, etc., even the user loadable speed table if I choose. Further, with the addition of a few transistors (to amplify the decoder’s function outputs), I can have any of the special lighting effects offered by the decoder.
Sound? Of course. Any DCC sound unit connected to a 12 volt car amplifier, powering a pair of 6” speakers will do. In fact, I already have the amplifier and speakers (with proper enclosure) installed.
The loco came with air activated braking hardware, it just wasn’t hooked up. After designing low cost pressure regulators and control valves, I went to bed one evening and a whole different system came to mind.
This system uses a small air compressor, tubing from the air compressor to the brake cylinders, a bleed hole, and compressor speed control.
Sound decoder function six is the default to activate the dynamic braking sound, and can be re-mapped to a variety of other functions. I’ll just use that same function on the motor control decoder to control a relay that will switch throttle control to braking control.
In operation, the relay will be relaxed, feeding power from the decoder to the H-Bridge to power the locomotive’s motor. When the dynamic brake function is turned on, the relay will be triggered to send decoder output to the air compressor instead of to the H-Bridge. When braking, you don’t want the motor being powered anyway. So, this scheme works just fine.
When powering the loco motor, throttle control controls how fast the loco will go. When powering the air compressor, throttle control controls how fast the air compressor will pump air. Considering that the air line has a small bleed hole, air will always be bleeding. But since the small bleed hole can bleed only a part of the air that the compressor is pumping, air pressure will build. And the faster the compressor runs, the more air will be pumped, and the higher the pressure will build. 25 pounds is about what it takes to lock up the brakes. Considering that the pump can get put out well over 100 pounds (without a bleed hole), there’s plenty of braking pressure. When the Dynamic brake function is turned off, power to the compressor stops, the air bleed allows all pressure to bleed, and brakes are off.
I’m using a cheap tire inflation compressor to start with, but will change to something a little more quiet once I have it all working and proven in actual operation.
The chassis, with motor (blue), is shown below. Batteries fit both in front of and behind the motor. You can see some angle iron brakes that holds one of them. |
