Showing posts with label power buffer. Show all posts
Showing posts with label power buffer. Show all posts

Wednesday, July 24, 2013

Progress Report 47

An almost unbroken spell of sunshine for around three weeks has led to quite a few running sessions and more than a few spells of continuous running while we've had barbecues or simply lazed in the garden. However, I have also taken the opportunity to finish off a couple of jobs and spend some time trying to sort out others.

Loco No. 4 Bulkeley

As mentioned in Progress Report 46, I have been working steadily on scratchbuilding a body for loco No. 4 - Bulkeley, based loosely on the Southwold Railway No. 4, Wenhaston. This was my first venture into building a steam outline loco but I used the skills I had acquired in building the Fowler diesel and rolling stock such the the cattle wagons to construct her largely from plasticard (see How I constructed an 0-6-2T Manning Wardle locomotive). The build was fairly straightforward though I did run into an unforeseen problem when she developed wheelspin on what seemed like insignificant gradients. I eventually tracked this down to the lower end of the bracket supporting the valve gear which was rubbing on the track. This was solved through the addition of an upper support bracket.

For a while, I was uncertain as to the livery of the original Southwold Railway loco - there seemed to be some ambiguity in the books on the SR which suggested she was lined out in light and dark green and yet the photos of the loco I had unearthed show no evidence of lining. After making an enquiry with the Southwold Railway Trust, I discovered that when delivered from Manning Wardle, she was lined.................

....... but when she entered service she was painted in plain dark green livery which she retained throughout her working life. However, towards the end of her life, her livery faded and her works livery started showing through.

My model has now entered service on the Peckforton Light Railway and for the moment she is sporting the line's livery of Brunswick Green (or in her case, Rover Brooklands Green from a Halford's rattle can aerosol). I am trying to decide whether to line her out in gold as with the line's other locos or whether to leave her unlined as a homage to her Southwold origins. You'll notice that I've positioned the loco's number beneath the nameplate as in her Southwold days.

She also has acquired a bespoke driver, made from oven hardening clay. I wanted to represent a driver or fireman passing over a token or just leaning out to watch the loco's motion. He's reasonably detailed though it looks as if his face has met with an unfortunate collision somewhere down the line.

The loco was my first real venture into battery power and after a few teething troubles I am steadily being won over to this form of power. However, I am also upgrading my DCC powered fleet (see below) to improve their reliability.

Adding DIY Power buffers to DCC locos

As all my track-powered DCC locos are designed around LGB 0-4-0 motor blocks it's inevitable that they experience problems when running slowly over the plastic frogs of pointwork. Last year, I invested in a Massoth Power buffer and added this to one of the locos to evaluate its effectiveness (see Progress Report 37). I was extremely pleased with the outcome and vowed I would equip all my locos with one. Despite its relatively low cost (under £25), having retired, funds are not always readily available and so when I came across an article in the French railway modelling magazine, Voie Libre, explaining how a modeller had added his own power buffers to his 0n30 locos, I researched the subject and found out how it can be achieved for as little as £2.50 per loco (see How I added DIY Power Buffers to my Locos).

 All my track powered locos are now equipped with power-buffers and, because I was hard-pressed to find a suitable location for the buffer in my Fowler diesel, I adopted the technique used in the original article and added the capacitor to the footplate to represent an air cylinder.

Working on the gearbox of the IP Engineering diesel loco

 I spent a day or so trying to build my own gearbox to replace the one supplied with the IP Engineering diesel kit, Jessie (see How I constructed a battery powered diesel from a kit). The gearbox as supplied used plastic gears and after only a very brief period of test running these became stripped of their teeth. I bought what I am hoping are more substantial metal gears from Cambrian Models but found that their 20:1 gears are not a direct replacement as the overall dimensions differ. I therefore attempted to construct my own gear housing from brass.

Whilst this worked to some extent, I found that as soon as even a small load was placed on the loco, the gears slipped (though only in reverse, the mesh was fine as long as the loco only travelled forwards). I am now attempting to construct a more reliable gearbox, building on the knowledge I've acquired so far and drawing on the expertise of a friend who has more metal working experience.

Improving the keyfob control on the railbus

After some interesting discussions on the G Scale Central forum about the merits of using a cheap 12v LCD dimmer unit to control a motor.
 

It seems that the unreliability which I had encountered over the speed control of the motor could be greatly improved through the simple addition of a diode across the output connections - see the excellent online article by Dave Bodnar.

I have disassembled my railbus (see How I constructed a railbus) and have duly wired in the requisite diode.

 At the same time I decided to replace the array of AA battery boxes I had used previously with a single 12v Li-ion battery pack which would take up considerably less room. Unfortunately, the pack which I had bought from China via a well known online auction site ceased to function and so I have been unable to test my newly adapted control board. Furthermore, I am growing increasingly concerned with the IP Engineering gearbox which at 16:1 does not provide sufficient torque to power both cars and I am assuming will ultimately strip its gears (see above). I am therefore investigating an alternative approach to powering this vehicle and will post an update when I feel I have made some progress.

More running sessions

 As indicated above, the weather has provided me with plenty of opportunity to run trains. I have continued to use my original freight handling computer program (see Computerised freight operation)  but have discovered that the freebie software I used to create the freight handling program will not work on Windows 7. I have fortunately found another programming environment which is not only free, it will create standalone programs to run on PC, Mac, tablets and smartphones (Livecode - which is based on the original Mac program - Hypercard). Once I have completed the re-programming I am hoping to be able to distribute various versions for others to use.

In the meantime, here is a small taste of some of the moments drawn from recent operating sessions.
The Down mid morning passenger approaching Bickerton
No. 2 Beeston on the afternoon Up passenger crosses the River Gowy between Peckforton and Beeston Castle
The daily pickup goods arrives at Bickerton with Hunslet No. 3 Bickerton
The pickup goods departs Bickerton on its way up the line towards Bulkeley
Shunting at Bulkeley
No. 3 emerges from the Copper Mine branch running light after delivering a fuel tank wagon
The Up pick-up goods approaching Peckforton where it will cross the Down afternoon passenger
 Now I have managed to sort out the slow running of the locos (see above), I take great delight in relaxing from time to time in a strategically placed garden chair as I watch each train slowly threading its way through the undergrowth from station to station. There is something very satisfying about seeing a train which I have created going about its business.

Saturday, July 20, 2013

How I fitted my own DCC power buffers

The things I enjoy most about my railway are slow running and shunting operations. However, as most of my locos are short wheelbase 0-4-0s I often get very frustrated when they stall or stumble on minute patches of dirt on the rail or when they encounter the plastic frogs of pointwork. As shunting requires a lot of slow running over pointwork, there are occasions when I have to bite my lip, mutter and count rapidly to 10.

About a year ago I fitted a Massoth Power Buffer to one of my locos (see Progress Report 37) and have been very pleased with the results. Although the power buffers are less than £25, having now retired, I felt the outlay to equip the rest of my loco fleet was something I would have to postpone until funds improved. All that changed when I came across an article in a copy of Voie Libre explaining (in French) how someone had added his own power buffer. A quick trawl through the internet unearthed an entry on the Massoth Users' forum by one of their technical staff explaining how a simple DIY buffer could be added to one of their decoders. As Massoth manufacture decoders for LGB, the same process can be carried out on their LGB's 'own brand' decoders.

Once the equipment has been purchased, the process is actually quite straightforward and took me only an hour (though on some locos, it took a little longer to create the space needed to accommodate the additional circuitry).

Before fitting the buffer, the decoder's CV29 has to be reprogrammed to disable analogue control. Without this, the power buffer would confuse the decoder into believing it was under analogue control and hence would ignore DCC commands.

The programming module was inserted LGB (55015) Universal Remote:

This was then wired up - the yellow and green wires into the transformer and the brown and white leads to the decoder via a piece of rail which I reserve for programming purposes.

CV 29 was then programmed by following these steps:
  • 1 - The loco was placed on the track and the transformer was powered up
  • 2 - The letter C appeared on the LED display on the handset
  • 3 - 29 was then entered on the remote's keyboard
  • 3 - 0 was then entered into the keyboard (this tells CV29 to accept 14 steps in digital only)
  • 4 - The right arrow was pressed on the remote
  • 5 - Provided everything is OK, the letter C should appear on the display
For each buffer, I bought three electronic items from my local Maplin store:
  • a 150 ohm resistor (product code M150R) - £0.32
  • a 35v 2200 uF electrolytic capacitor (product code VH55K) - £1.49
  • a 1N5400 diode (product code QL81C) - £0.52
  • Total cost =  £2.33
The diode and the resistor were soldered together in parallel.


These were then soldered to the positive lead of the capacitor and a plain (red) wire was soldered to the the other end of the two components. Another (grey) wire was soldered to the negative lead of the capacitor. The whole assembly was then shrouded in insulating tape to help avoid accidental short circuits.

Connectors were soldered to the other ends of the wires and these were then pushed on to the D+ and D- tags on the Massoth L decoder (this is identical to the LGB 55021 decoder).

The decoder and buffer were then inserted back into the loco and the loco re-assembled.

Yes, it really was that simple, but the proof of the pudding ..............

For me the advantages of this system far outweigh the disadvantages. The loco won't run on an analogue powered railway and the the CVs (including the loco channel number) cannot be programmed unless the power buffer is disconnected. However, as it is connected to the decoder's power feed tags it's a fairly easy process to remove the buffer should the decoder need to be reprogrammed. Alternatively, a switch could be wired into the feed to the buffer should I want to more easily disable the buffer.