Banbury_in_00 (Posts about track)

Corking

Tim Pearson — Wed, 17 Sep 2014 12:00:00 GMT

Back to laying down cork; this time I have the additional problem that I want the edge of the cork to be a 60 degree angle where there is no platform and a right angle cut where there is a platform. This is further complicated by the fact that the platforms at Banbury (like at many stations) have a considerable overhang - I have looked at these for sometime (hard to measure without getting yourself arrested) I believe the overhang is about 9 inches.

The road bed needs to be wider where there aren't platforms too. In order to make marking and cutting the cork as accurate as I could, I printed out two full scale plans from xtrckcad - one with a roadbed width of 39mm, which I used where there was a platform and one with a roadbed width of 44mm which I used where there was no platform. I then combined the two and used an angled cutter where there was no platform and a knife held normally for platform edges.

The 5mm difference is more than the scale 9 inch overhang would be (it is between 14 and 15 inches) but the angled profile outside the platform areas reduces the effective width.

More Appch Wiring

Tim Pearson — Sun, 05 Jan 2014 12:00:00 GMT

Still cracking on with the Northen Approach board wiring - getting bored with it now.

Whilst in some ways I wish I had bought DCC Concepts cobalt point motors instead of the Tortoise motors I am using (because their smaller size makes for less problems in squeezing them all in) One thing I like about the tortoises is that you can have a harness with an edge connector which you can just pull on or off as you are building.

In the picture you can see the blue edge connectors attached to some of the finished motors.

A chance to make some progress

Tim Pearson — Sat, 28 Dec 2013 12:00:00 GMT

After a stupidly busy couple of months, the Christmas break has allowed a few days of fairly continuous work on the approach board (that I see from this blog I started in June).

I now have all of the points mounted on the northerly station approach board...

The flange screws you can see between the rails holding the trackwork in place are to allow for minor adjustments, the track will eventually be glued into place when the track is ballasted (at least a year away) and at that point the flange screws will be removed.

I want to check that the track runs perfectly before gluing it down.

I just can't work kneeling down for more than a minute or two so I have tried to make the construction of the layout as modular as possible - such that I can either work at my workbench or at least standing up. To that end the boards are all to some degree removable and the electronics are as modular as possible...

This board is the most complex, it requires 14 point motors and the track-work is split into 15 separate occupancy detection sections. This is because the complex station throat point work has so many possibilities that the required continuous track detection is tricky.

Continuous track detection means the computer never has to guess where a train is. It requires two things - (1) all track be occupancy detected (2) no single occupancy sensors are going to have two separate trains on simultaneously under normal operation.

The electronics for this board (like all of the electronics) hangs on hooks from a supporting L-girder in this case it contains 2 CML DAC-20 Digital point controllers and one Digitrax BDL-168 occupancy detector board.

The feeds to the track and points are mounted along the top on pluggable connector blocks, the feeds into the electronics are two cables attached on the right hand side by locakble circular connectors - one carrying the track feed and one the various power supplies required for the electronics.

There are 6 separate track feeds that come from two central Digitrax PM42 boards - these mean that any short circuit is more easily identifiable as it only affects one area of the track. One track feed goes to each of these hanging electronics boards. The whole board is assembled on the workbench and then can be plugged in when in position with no further wiring required, thus saving my knees.

Hacked Slips

Tim Pearson — Tue, 05 Nov 2013 12:00:00 GMT

I Really like the modifications to the standard PECO point that DCC Concepts recommend in their very comprehensive downloadable cobalt instruction sheet. However for the double slips - which are expensive (£30+ ea) the thought of replacing the plastic sections with soldered copper clad was not for me, therefore I settled for trimming the plastic down to reduce the offensiveness of the original moulding...

Here you can see a sort of before and after

Laying Cork and Thinking Track

Tim Pearson — Sun, 02 Jun 2013 12:00:00 GMT

I have been really busy working on a smartphone video monitoring system called Manything lately so haven't had much time for modelling...

LINK}:-http://www.manything.com; Manything Website;

The odd moment I have had, I have cut and laid the cork for the track work on the station approach board. As this is the first scenic section I have cut the cork at a 60 degree angle in order for the ballast to sit nicely on it.

I made the cutter shown below by cutting a piece of 2x2 at 60deg using the compound mitre saw, and the screwed a box cutter blade to the surface - it seems to work ok.

I have also tried using the suggestion from Richard at DCC concepts to modify a peco point to take away the horrible chunks of plastic that make it look very unprototypical.

The modification requires soldering copper clad sleepers to replace the original yeuchy plastic.

MicroSwitches

Tim Pearson — Mon, 10 Dec 2012 12:00:00 GMT

I have a small number of SEEP point motors. I prefer to use tortoise for the majority, but there are some locations where space is at a premium and the much smaller SEEP seemed to be the answer.

Alhough I bought SEEPs with built in polarity switching - I didn't find it reliable, so I bought some microswitches and placed the reed part of the microswitch so it would be moved by the bottom part of the actuating rod that moves the point.

Whilst this sorted the polarity swtiching problems - in practice I just couldn't make the SEEPs reliably reliable - too often they would not throw. On advice from Laurence at CML I upped the voltage of the SEEP feeds - but whilst an improvement still didn't give me the reliability of switching that I want. Therefore all bar one have been binned and fiddly work has been done to put tortoises in their place.

The picture below shows one of the microswitches I used... .. thumbnail:: /images1014/microswitch.jpg

Fiddle Yard fairly Complete

Tim Pearson — Sat, 08 Dec 2012 12:00:00 GMT

I am just about done with it now - here are some pictures. The grey blocks are the supports for the reversing loop overpass that I can't complete until I have built the baseboards along the adjacent wall - as they contain some supports for it.

Making the supports exactly the right height and to a very odd cross section has been hard - eventually I glued three pieces of 24mm ply toegther and that is about right.

Fiddle Yard Construction

Tim Pearson — Fri, 03 Aug 2012 12:00:00 GMT

I have spent much of the last few months making slow but steady progress - I have built four of the control boards I need - including the power distribution board which contains 2 x PM42 power distribution thingys from Digitrax. This allows the network to be separated into a number of separate power feeds - on a large layout like this it also helps short circuit detection in that you can immediately see which area of the network you have a short on. Finally it does the job of inverting the polarity for the reversing loop. The power distribution board also distributes three other AC and DC supplies for powering various things - You can see it propped up on top of the basebaord on the left of this picture...

It does seem though that I have enough power feeds to supply a good section of the london underground!

I have also installed under the reversing loop slope section an infra-red detector to automatically change the reversing loop point whenever a train is approaching it. This works well apart from the fact that it doesn't always initialise to the correct orientation - I have not investigated cause or solutions to that yet.

Hopefully I can now lay the track for the fiddle yard quickly as I have built the control boards to supply all of the points - 14 or so and all of the detection sections 28 or so.

One of the reasons for my lack of updates on this blog is the update to Mac OS X 7 - my own blog writing software (written in objective-c) used older Operating Sytem calls no longer supported in OSX 7.x so I had to open up the software and fix it - a trivial job in itself but downloading the latest development environment on my slow link and educating my slow brain in the changes to the OS API was a big obstacle! .. thumbnail:: /images1014/FiddleYardBaseboards.jpg

Track Plan Finished

Tim Pearson — Wed, 08 Feb 2012 12:00:00 GMT

well at least enough to start some track laying!! I am sure I will keep making changes.

After several hundred iterations - seriously - the track plan is complete enough to start some track laying - I have made a number of revisions to the station area again to better align it with the scale drawing.

The jpeg below shows the track plan overlayed on the scale drawing as a test to see if it is good enough.

As I said earlier the comparison is slightly false in that I have had to squash the scale drawing to make it fit in a reasonable length - that changes the aspect ratio of it rather - you can't shrink it in both directions as the platform widths (especially on the bay platforms) become untenable.

Track plan based on scale drawing

Tim Pearson — Mon, 06 Feb 2012 12:00:00 GMT

Here is the latest revision of the track plan now with a curved station based on the scale drawing - note that even in the space I have available the station doesnt really fit well - it would require well over 5m in length and so I have squashed it up a bit.

Also note that the scale drawing is of the contemporary station wheras I am trying to do the 1962 version.