Problems

Hi folks,

No post for yesterday, I was working on a customer order - hooray! Some small jobs have been creeping onto the books so things look OK for this month.

My Father's PC has died and despite all my efforts it would appear that the motherboard has given up the ghost. This is causing him some grief because, since my mother died 18 months ago, his PC has been a bit of a lifeline to the outside world. It seems that the hard drive data is intact so we should be able to get him back up and running again.

I went to price up a job to fit a replacement shower this evening, it would have been a straightforward job since it's an instantaneous electric one and the element had burnt out. However, on actually viewing the site I became far more concerned with the fact that there is an obvious leak, either in the water feed or the waste pipe system. The ceiling of the kitchen below has become so water logged that a section 4 feet by 4 feet in in danger of falling down!

I'll be on site tomorrow so we'll see how we get on.

The model railway has hit it's first major hold up. I've spent a lot of this week wiring up the electrics to the control box. In the images below you can see the wiring loom for the isolating sections and the point motor switches. Note that as yet there are no electronics for the controller installed. This is because I have 4 different prototype designs in the testing stage and I don't know which one will be fitted yet. In the meantime I am just using my loco testing controller for some running tests.

Once the box was wired up I began testing the track for correct operation. In the lower photo at the top you can see the small 6 wheel diesel shunter used for the tests. I use this because of it's short wheelbase which is likely to show up any losses of contact over points and suchlike.

On testing I found that all the isolating sections worked as they should and all the point motors were firing as they should, but I was horrified to discover that only 4 out of the 7 sets of points were changing correctly. The nature of the problem soon became evident. The points are thrown by simple solenoid switches, one can be seen in the image below.

Similar ones to these are manufactured by Hornby, Peco and these known as Seeps.

The travel required to throw the N Gauge points I am using is only 2mm, but because of the thickness of the baseboard I chose to use for the station, the drive pin is flexing such that the motors maximum travel of about 10mm is not enough to throw the point!

Having examined the motors carefully some have a fraction more play in the solenoids than others. Only by a factor of about 1/2mm but when this is multiplied over the 25mm of the drive pin it is enough to fail to throw the points.

There are a number of possible solutions. I could dump the entire base boards and start over using 6mm MDF throughout, not a palatable idea. I could revise the mechanical linkage, possibly for a crank based system which would allow the motors more travel and more torque, I am still toying with this one. Or I could route out recesses for the 3 point motors that are suffering, thus reducing the length of the drive pin and eliminating the flexing. At the moment, the last is the most favourable but also the most messy to perform with all the under board clutter.

Mounting the motors above the baseboard and 'hiding' them would have been an option but the layout planning has not allowed for this. If anyone out there has been following this blog and is thinking of modelling in N Gauge, don't use a baseboard thicker than about 9mm if you are mounting the motors beneath the board.

The next railway post will include my resolution to this problem, and a discussion of the electronic systems.