5.26.2005

back to the trains

Planning for the next On30 modular group "build session" is underway. We have not decided upon which DCC system we will be using for exhibitions. The decision to go wireless was very easy; the benefits are worth the initial expense. However, each of us has a different ideal throttle configuration.

I am a Digitrax user. I prefer their UT series "knob-and-switch" throttles. Not the most robust construction, but certainly adequate to task. The new UT4 & UT4R have full function control and 4-digit addressing. For programming I always try to use the PR-1 programmer PC interface.

I have used Lenz and find it very nicely built. Both of their pushbutton and knob style throttles are fine and feel comfortable to use. The CVP radio throttle add-on system for Lenz is OK. I found the narrow handheld a little uncomfortable, but I suspect that some trimming of flash on edge the plastic casing will soften it up. Not having used NCE or Atlas, I cannot yet comment on their "feel".

I've also had the chance to use old carrier-based CC systems like Keller OnBoard and PSI Dynatrol. The PSI throttles with full train-brake simulation are a real treat. I don't know how well they've implemented that feature now that they offer a DCC compatible system.

I'll bring the Digitrax setup to the next build session and let the other members have a go with it. The plan is for each of us to buy one radio throttle (for whatever system we decide upon) and split the cost of a receiver panel 4 ways.

5.20.2005

fortune smiles (gearing)

I was in luck yesterday. A spontaneous trip to a not-so-local hobby shop yielded a selection of NWSL components at very low prices. Two such gems were re-gearing kits for HO MDC steam locos. These are 72:1, compound reduction designs (sans gearbox surround). The gears are intended to drop into the MDC die-cast chassis, replacing the stock set. Low speed operation and pulling power are greatly enhanced.

I will be using them for other projects than HO, of course. My dad is the HO modeller; I wander about in scale and gauge, era and theme so much that I no longer say, "I'm in X scale", or even, "I'm a Canadian National modeller".

The other source I patronise for gearing is Ultrascale in the UK. They carry (and will produce) a wide selection of gears up to 100dp. Another promising vendor with gearboxes up to 108:1 reduction is High Level Kits who have, so far, remained unresponsive to my inquiries. Perhaps my requests have been lost in the ether.

I must remember to pick up some 3mm and 3/32" oil-hardened drill rod for larger axles and shafts. The 1/16", 2mm, and 1/8" stock on-hand will be sufficient for smaller applications. The practice of substituting 2.4mm stock for 3/32" works fine, as the dimensions vary just over 1/2 a thou, which should not affect a press fit in this case.

5.12.2005

On30 module (part 3)

The ditches have been formed, the cork roadbed is in place, and the sugar pine ties have been laid. A slight dip just before the bridge will have to be corrected before ballast is applied or rails are spiked. I was able to determine that the original alignment included an 18" radius, rather than 22" as I'd hoped. This will limit some of the equipment that can operate on the module.

A few observations:
a) The expanding foam-in-a-can is NOT hotwire friendly,
b) do not apply plaster prior to your hotwire work,
c) wear static-free clothing while carving foam, and
d) make the top layer from a single piece if possible.

The cork is being fastened with No More Nails adhesive and has been pinned in place while it sets. A single 5" wide piece of Mid-West cork yields 12' of 1-1/4" wide strips that will bend around an 18" curve. If I recall correctly, one piece of 5" wide sheet was cheaper than 12' of bevelled HO roadbed.

5.11.2005

a note on gears

Do not discount "other" hobby factions when looking for model railway components. For instance, I found what I hope to be some suitable 64 dp aluminium gearing in a shop catering to R/C car enthusiasts. The prices were reasonable and the selection quite surprising. Large scale modellers would certainly be able to utilise gears in the 48 or 32 dp range which are also available.

The gears are designed with a hub and grubscrew for fastening to the shaft. I will have to face the gears down in thickness to reduce their space requirements. I will also eliminate the hub and aim for a press fit on the shafts.

If the loads are sufficiently low, plastic gearing intended to repair R/C servos could be employed. Sets are available in a bewildering array of choices. Given their intended application as torque multipliers in a servo, the ultimate reduction would be quite high.

hold the phone

Looks like my personal projects are getting put on hold. It seems that several people suddenly want model railroad items built or modified. In the last 7 days I've been told to go ahead with 5 tasks that have been, up until now, merely hypothetical.

Am I pleased? Certainly! This bodes well for the future.

One is a particularly large endeavour; 1:22.5 to be exact. Two more are CAD projects for a model railway kit manufacturer. The remaining pair are repair/rebuild issues dealing with 1:64 scale items.

On30 module (part 2)

The inside fascia is now on the module. A wavy profile was cut into it to encourage steep hillsides and their associated scenic necessities. Since the module is intended to be viewed from either side, the high vantage will make for an interesting viewpoint.



In honour of a memory which is fading and mellowing with time, I have decided to call the module "Whisky Creek". I am using the Scots spelling of the word, so please don't email or comment telling me I've left out the "e". I have nothing against Irish tipple; I enjoy Redbreast and Black Bush whenever the opportunity arises. While it bears little resemblance to the actual location of my childhood, I'll always recall a pleasant vision when I say the name.

As mentioned before, this module is a bit of an experiment. It is being formed "inside-out". The foam was cut and shaped prior to the addition of end plates or fascias. There will be some compromises in its construction due to an undeniable lack of planning. That I am able to salvage this unit from a previous set of trials is a bonus.

I have some concerns in terms of robustness due to the odd way in which it is being built. The main worry is the long-term stability of the end plate-to-fascia joint. This is made using only two or three #8 x 1-1/2" particle board screws (Robertson head, of course) at each end. It may be possible to notch the foam to make sufficient space to retrofit inside corner blocks for stiffening.

5.04.2005

narrow gauge turntable drive


Part of a turntable mechanism built for a good friend. The pivot is a 1/4" mono phone plug and jack combination. A brass bushing was made to accept the cable end of the phone plug, and a nylon gear was bored out to fit the outside diameter. A brass plate to support the superstructure (built separately) was affixed to the top of the bushing. Power fed from the tip and ring contacts on the phone jack allows for sound equipped locos to remain uninterrupted throughout the turntable rotation. The wires are run from the plug solder tabs up to the rails inside the bushing body.



The turntable is powered by a Switchmaster stall motor mounted on a spring loaded swing arm. The spring keeps the stall motor pinion gear in mesh with the bridge pivot gear. The entire bridge can be removed from the top of the layout for maintenance or detailing by simply pulling upwards. A Lenz automatic reversing relay deals with the polarity change during rotation.

5.02.2005

current project (part 1)

When I can manage to get the link up and running, I will have a honey of a Current Project to share. It's a devilish little 0-4-0 infernal combustion loco kit that has seen better days. At some point it might have been an adequate runner, but that is not longer the case.



The motor and gearbox design would be fine if the whitemetal castings hadn't worn away around the axles. Now the gears do not stay in mesh. When they do decide to connect, it jumps and bucks like a startled deer. There is no slow speed control due to the negligable reduction in RPM through the use of a terribly small diameter worm wheel. Slow speed running will have to be addressed during the rebuild.

I have an idea that will increase the gear ratio, provide a 3-point suspension, and permit the addition of a small flywheel. This will involve a complete chassis fabrication, but it will be well worth the effort in terms of performance and reliability. Further bulletins as events warrant.