Monday, 8 May 2017

Getting to the point!

A bit of an update on construction ofmy new layout "Smestow"
A start has been made on laying track and points on the scenic sections of the layout. I decided to use the new Peco code75 bullhead rail and chaired track and my first impressions are quite favorable,
It compares well alongside the C&L finescale track that I've used on previous projects, the advantage of the Peco version though is that the sleeper thickness is the same as their original code 75 flat bottom Steamline track making it is easy to connect up to Peco's turnouts and crossings, even the old Peco rail joiners can be used.
I'm also using up a few yards of C&L track that I had in stock, but because the sleepers are a lot thinner I have had to glue a strip of Evergreen 0.125in x 0.030 in under each individual sleeper.
A bit time consuming but worth the effort.
I;m using Peco code 75 turnouts, unfortunately Peco have yet to start to make point work to match the new bullhead track but having laid a couple of points and a yard or so of bullhead track the mis match isn't visually that bad, I reckon by the time the track is painted, ballasted and weathered it will look OK.

I'm going to use small servo motors to operate the turnouts and started looking at the different ways this can be done.
After watching a few methods on
U tube I must say that i wasn't too impressed by some of the Heath Robinson methods used.
I eventually found theses devices on Ebay quite cheap too, so I ordered a few to try out.
Made from lazer cut 3mm plywood they just need a bit of glue to put together.

The picture above shows the servo mount in flat pack form as they come from the seller on Ebay.
!5 minutes work, a bit of glue, some screws and a piece of piano wire later they look something like this,

The micro switch will be used to operate a small relay, the contacts in the relay are then used for switching the point frog polarity and also operating L.E.Ds on the control panel to indicate the turnout setting.  The frog relay can also operate other relays and devices so that I can interlock points and signals and so on.

Cost wise, using servos is not a cheap alternative to using solenoid type point motors in fact the cost is probably at least twice that of using solenoids but, in my humble opinion operation by servo is far better.
There's no big thump as the point changes therefore there is less chance of any damage to point tie bars and mechanisms. I also removed the over centre spring and associated non prototypical bits of plastic in the centre of the track, hopefully that will give a better looking uncluttered look to the pointwork.
Operation is smooth quiet and reliable so far so good!






Finally,
Here's a picture of two of the above servo motors under a 3 way Peco point viewed from under the baseboard.
The motors are in this case under the control of a "Heathcote Electronics" control board.
Again, these are not the cheapest controllers around but, like everything else in this world you get what you pay for and the quality and build of these units is good.
However, since I aquired the Heathcote circuit boards I have joined MERG (Model Electronics Railway Group)  and I'm very tempted to order a couple of "Easypoint" kits from the members only kit locker and try those on some of the other points and signals.
I'm going to need to drive at least 12 points and signals so the MERG kits have got to be worth a try.




Well that's the update so far, I'll post more as and when things happen.
Cheers for now    Frank




Monday, 24 April 2017

Well connected

I've made a start on the wiring for Smestow.  I know it might sound a bit backwards to some that I have started the wiring before laying any track on the scenic sections of the layout but, the idea is to do as much of the basic wiring as possible so as each section of track is laid it can be tested and checked as work progresses.

I'm still sticking with conventional DC control for locomotives and other traction but I'm also developing my own local bus system for control of servo point and signal motors. This should reduce the number of wires going back and forwards to the control panel.

MERG have a range of similar modules in the members kit locker but I enjoy experimenting with electronics and I'm in the process of designing and building my own local bus system using cheap and easy to obtain parts from several sellers on Ebay.

 This was the state of play with some of the wiring this morning.

Note that I use good old fashioned solder tag strips rather than the screw connector blocks.
Just my personal preference as I always think that a good solid soldered joint is far more reliable than screw terminals.

I find that screw terminals have a tendency to shake loose over a period of time and throw up all sorts of faults.

Having said that, some of my modules will have screw terminals just to make a quick disconnect and removal of modules for any modifications and alterations that I might want to make.

The picture shows the underside of the end base board and the solder tag strips can be seen, the tags are wired to a 25way D connector that will connect the control panel to the layout.

The circuit board in the centre is just a 15V DC distribution board and feeds power to other modules individually.
Below that is the 5 V DC power supply to provide power to the servo motors.
I'm using a bit of a mixture of servo drivers for the points and signals. I have some Heathcote electronics modules salvaged from one of my old layouts and some MERG servo drivers that I haven't used before but at the price for the kits are as cheap as chips.
The only drawback with the Heathcote modules and cheap Ebay servo motors is that the servos tend to kick quite violently on power up. To overcome this I have incorporated a timer circuit in the motor supply line.

On start up power is applied to the control modules immediately, but there is a two second delay before the motor power is applied. this gives the control modules time to settle down and stops the servos from jittering on power up. .
As I said earlier some of the control modules are still in the development stage but I will update this page as and when things develop.