The Furness Valley Railroad

[Donw]

I knew Crimson was one of those colour affected by the undercoat I never realised quite how much. Very interesting Chaz

 

Don

[AJon30]

Thanks, very useful

 

Rgds Andrew

[chaz]

Foreground has the card weave added, tacked to card formers with a hot-glue gun.

 

 

The first section on the left has been painted with PVA and some tissue paper added.

 

Taken late last night....

 

 

The tissue paper has reached the tunnel mouth, I have added a first layer of paper mache to the first section, topped it with more tissue paper, and prepared two more lengths of crib wall. It's beginning to look like a landcape.

 

I can't dodge it much longer, I am going to have to start making trees soon......

 

Chaz

Edited August 28, 2015 by chaz

[chaz]

Here is the screen for the staging spur with the crib wall attached.

 

 

It is on the bench to have the card weave added. A fiddly job and not perfect, but "dodgy" bits can be smoothed out with paper mache and hidden with foliage.

 

I also made up a removeable piece to fit between the end of the crib wall and the tunnel mouth.

 

 

Like the crib wall I made up the planked retaining wall on black card. This ensures that any slight gaps do not show.

 

The next photo shows the two sections in place and doing their job, screening the spur.

 

 

Next job is to sort out the gap at the other end of the crib wall. Needs a bit of thought as I do want to be able to remove all three sections if I need access to the spur. The tunnel mouth and the hill behind are fixed - one advantage of 1:48 scale is that there is no problem putting a hand into the tunnel to clean the rails.

 

A bonus to making these sections lift out is that they can be put on the bench to do more work, making the crib wall convincing etc.

 

Chaz

[2ManySpams]

Nice bit of timberwork there Chaz. You've an eye for landforms.

[chaz]

 

I have extended the crib wall a bit further to deal with the slope into the corner.

 

 

The corner is where a chimney protrudes into the room. I think I will have to rely on some closely packed trees and undergrowth to make this awkward area acceptable.

 

Chaz

Edited August 31, 2015 by chaz

[chaz]

When the scenic screen is in place it will be impossible to see the spur or any stock on it - well that is the whole point of a screen! However I will need to know when stock is getting near to the end of the track to avoid derailments, damage to couplings etc.

So I have installed a sensor to the track hooked up, via a simple electronic circuit, to an indicator LED. This lights when a piece of rolling stock shades the LDR.

 

 

In the photo above on the left is a high-intensity white LED and a resistor mounted on a piece of matrix board, which is soldered to a brass bracket. On the right a similar arrangement of board and bracket carries an LDR (light dependent resistor).

 

Next photo shows the electronic circuit - also on a piece of matrix board.

 

 

You can see that it is a very simple circuit.

 

If you would like details just click "like" and I will post a circuit diagram, component list etc on this topic.

 

Chaz

Edited August 31, 2015 by chaz

[chaz]

I will post details of the detector circuit soon, meanwhile a clearance test...Oh, alright, I'm playing!

 

 

Ten-wheeler #25 emerges from the tunnel with a rake of loaded coal hoppers in tow. A motivating snap and useful to get a sense of scale. These quarter inch scale models certainly have presence and this one will gain more when I weather it.

[chaz]

As promised - details of the detector circuit...

 

This is necessarily "tecky" - skip it if you want. Feeling brave? Read on.

 

Circuit diagram

 

Component functions

LED1 is a high intensity white LED used to make the "light beam"
LED2 is the indicator which lights when a train breaks the beam
LDR changes its resistance as the light falling on it changes - its resistance goes up as it gets darker
IC1  - the "chip". It switches the output on and off as the light level changes up or down.
R1 and R3 limit the current through the LEDs
VR1 - makes a reference voltage for the inverting input (pin 2). When this voltage is the higher the output (pin 6) switches off.
R2 and the LDR make a potential divider and set a voltage for the non-inverting input (pin 3). When this voltage is the higher the output switches on.

Component values

IC1 is a CA3140 operational amplifier.  An integrated circuit ("chip") in a DIL8 package. DIL8? - dual in line with 8 pins, that is two rows of four. The numbers on the diagram show which pins we need to connect to what. Pin 7 is connected to + volts and pin 4 to 0 volts. Pins 1, 5 and 8 are not connected in this circuit. I have included a sketch of the DIL8 pin-out on the circuit diagram The chip should be fitted into a DIL8 socket - it's considered bad practice to solder a chip directly into a board.

R1 & R3 - I used 1K0 (brown black red gold) which works fine but on anything up to a 12V supply you could reduce this value to get brighter LEDs.
R2 - 100K (brown black yellow gold)
VR1 - any 3 pin potentiometer of 10K or more will do fine as we are making a reference voltage - current is not an issue. I put a miniature 50K on the board as I expect to adjust it once when setting it up. if you expected to adjust it often - to cope with changing light levels - you could use a panel mounted variable with a knob and connect it to the circuit with three flying leads.
LDR - either an ORP12 or the miniature version I used will work fine.
You will also need a small piece of matrix board and some uninsulated single strand wire for wire links. I prefer to wire to a tagstrip and then on to the layout. If you do this you will need one with six tags (nine if you are going to mount the variable resistor remotely).

How it works

The circuit uses a CA3140 operational amplifier (op-amp) to make a very sensitive sensor called a comparator. It compares the voltages on its two inputs and switches its output on or off depending on which input has the higher. In my circuit the voltage on one of the inputs is set by VR1, which can be adjusted to give the best switching action - you can set the switching level and make it more sensitive or less. The voltage on the other input is set by a potential divider formed with a fixed value resistor (R2) and an LDR (light dependent resistor). I have mounted a high output LED (LED1) on one side of the track and the LDR on the other. A piece of rolling stock interrupting the light from the LED and shading the LDR causes its resistance to rise. This makes the voltage on pin 3  rise. If it rises above the voltage set on pin 2 the output of the comparator will switch on. There is no need to measure the input voltages, when you test the circuit setting the switching level is easy.  Should you want the output to turn off rather than on just swap the connections to pins 2 & 3.
The CA3140 output will source up to 40mA which is more than enough to drive an indicator LED. Connect this between the output and 0V, with a resistor in series (R3) to limit the current. The circuit will work on a 9V or 12V DC supply, indeed the op-amp will cope with supply voltages up to 36V. If you do use a higher voltage it would be wise to increase the value of R1 & R3. The circuit does not need much current  - so an old plug-type phone charger is ideal, the one I am using is marked 9V 200mA. It will also work fine from a PP3 battery.  The supply must be DC - AC will destroy the chip.

 

Testing the circuit

 

When you first power up the circuit put a thumb on the chip. If it starts to get hot turn off immediately and check what you have done. Don't wait for the smell of burning plastic.   Look for a short circuit with a solder bridge between two tracks or a mistake in the connections. If the chip stays cool, with the LDR unobstructed turn VR1 until the output LED is lit. Now turn it slowly until the LED goes dark. If you can't get the LED to turn on and off when you turn VR1 disconnect or turn off the PSU and check the circuit.

Next obstruct the light beam with something opaque - the output LED should light. Remove the obstruction and the LED should go dark. Yes?

Go ahead and install the circuit on your layout.

 

tag strip connections - from the top...

 

1. red - from PSU + volts
2. black - from PSU 0 volts (you could call this minus- it's even marked that way on batteries - but it's not correct)
3. green - to LDR
4. black - to LDR
5. white - to indicator LED anode (long leg)
6. black  - to indicator LED cathode (short leg)

All three black tags are connected - they are all at 0 volts.

Pros and cons of the circuit

For

The circuit is very reliable and gives a clear digital output - it's either on or off.
It is adjustable to cope with a wide range of lighting - indeed if there is enough ambient light you may be able to dispense with LED1.
No wiring is needed to the track - the circuit is entirely independent of the layout wiring and can be used on both DC and DCC layouts.
It will sense both locos and cars - neither of which need be modified.

it will work with models to any scale.
The sensor will work either horizontally (across the track) or vertically, with one component between the rails and the other supported above.
The most expensive item is the IC - Rapid Electronics list the CA3140E at £1.20 and an LDR from the same supplier will cost about 50p - I would expect the whole thing to cost no more than £4.

Against

 

You need to be able to source the components and assemble the circuit - and you need to be reasonably comfortable working with electronic components.
It might be difficult to disguise the sensor pair - not a problem on a hidden track! But I can't imagine wanting the detector for a position in plain view.
The LDR and LED will need supporting on some sort of bracket - it could be difficult to find room for these. I cut a hole in the back of the scenery for my LED.

 

I hope that's helpful. If you want to try this for yourself I would be happy to answer any questions you might have.
 

Edited September 1, 2015 by chaz

[chaz]

Spent some time today installing the optical detector.

 

 

I fixed the board to a baseboard leg to give easy access for the wiring.

 

I tested the action with a rake of six Bachmann two-bay hoppers.

 

 

And as I had done more work on the scenery I took this....

 

 

I still have some work to do on that gap on the left. Tricky as the crib wall section removes. It will be very easy to jam it in place.

 

More soon.

 

Chaz

Edited September 1, 2015 by chaz

[Donw]

That circuit takes me back Chaz. I remember playing with OpAmps at college. Useful things.

 

Don

[chaz]

That circuit takes me back Chaz. I remember playing with OpAmps at college. Useful things.

 

Don

 

Took me back as well Don. It's probably been ten years since I made this circuit for a previous layout (where it was used to detect whether a loco had cleared the point blades that were inside a tunnel mouth). I had forgotten much of this stuff and had to search out the details, which fortunately I had filed away. In fact it had a 741 in the socket but swapping it for a CA3140 meant I could dispense with a LED driver transistor.

 

Chaz

[chaz]

This morning I did some work on the slopes over the tunnel...

 

first the card weave, fixed with the hot glue gun - tricky to get it right in under the ceiling.

 

 

Next the weave is covered with a couple of layers of tissue paper, glued with PVA. I covered the track through the tunnel with card to prevent any drips falling on to it.

 

 

While the PVA was still a bit tacky I added a layer of paper mache.

 

 

This will all be given time to dry out before I do any more work on the area.

 

I plan to paint all the paper mache before I start adding grass, weeds, shrubs, undergrowth, trees etc. What colour to use? A light grey with a brownish tint? I want to avoid glimpses of the white paper mache showing through the greenery.

 

Chaz

Edited September 3, 2015 by chaz

[AJon30]

What part of the US is the layout based in? You had a mock up earlier with a lot of trees around the tunnel, have you moved away from that?

 

Rgds Andrew

[chaz]

What part of the US is the layout based in? You had a mock up earlier with a lot of trees around the tunnel, have you moved away from that?

 

Rgds Andrew

 

No Andrew, I still intend there will be lots of trees - but they will take time to make.  "What part of the US?"  In the East, possibly Pennsylvania and I imagine the line running through a wooded valley. Lots of broadleaf trees, rather than conifers. I want to paint the paper mache shell before I start adding greenery to avoid the white showing through.

 

 

The shell to the right of the bridge has been painted with grey/browns - I am wondering if the colour is too dark? I expect most of this colour to disappear later under greenery.

 

Chaz

Edited September 2, 2015 by chaz

[AJon30]

So East Broad Top area? Yes that gray looks a little dark then

 

 

Plenty of trees

 

 

Rgds Andrew

 

[Donw]

I used a bit of emulsion described as Mushroom on some recent work. I had smeared a bit of polyfiller over the paper mache first colour was quite light rather like a chalky area

 

The soil colour (should that be color on this thread?) will be affected by the geology. It has a reddish tint in Minehead lovely sticky red clay which is the natural rock in a line which passes through Bridgenorth, Minehead and Exmouth.  Andrew's pictures above suggest something a tad darker than the mushroom.

 

I like the work on the tunnel. I assume the sloping ceiling will get a coat of sky colour. My loft has sloping ceilings and I ought really have big mountains (well to be precise Cader Idris which is quite big) on the backscene but with a sloping ceiling it would lean over the layout. I wonder what your approach is.

Don

[chaz]

 

 

I like the work on the tunnel. I assume the sloping ceiling will get a coat of sky colour. My loft has sloping ceilings and I ought really have big mountains (well to be precise Cader Idris which is quite big) on the backscene but with a sloping ceiling it would lean over the layout. I wonder what your approach is.

Don

 

 

Plan at the moment is to keep the ceiling white. With it so low, in fact touching the scenery here, it will always look odd even if painted. IMHO it's better to leave it quite plain, painting it would only draw one's attention to it - after all we don't paint tree roots and rock strata on our baseboard fronts do we?

 

Chaz

[chaz]

So East Broad Top area? Yes that gray looks a little dark then

 

EBT 2.jpg

 

Plenty of trees

 

EBT 1a.jpg

 

Rgds Andrew

 

Two very interesting photographs Andrew, thanks for posting them. I like the overgrown look of the roadbed in the second shot, some of the FVRR may end up with this effect.

 

Can you date these pictures?

 

Chaz

[AJon30]

Top one is Oct 9 2004, the bottom one I believe is 2008. As you may be aware the EBT has not operated for a number of years but hopefully should be back operating in the future. There are plenty of photo's on the web of EBT trains and locations

 

Rgds Andrew

[chaz]

I know very little about the EBT so after seeing Andrew's posting I googled it and read the Wiki stuff. Fascinating that the line and most of its equipment survives. It's an interesting parallel with the Ffestiniog in North Wales which was also abandoned, but left largely intact so that it could be revived.

[CourthsVeil]

...

I plan to paint all the paper mache before I start adding grass, weeds, shrubs, undergrowth, trees etc. What colour to use? A light grey with a brownish tint? I want to avoid glimpses of the white paper mache showing through the greenery.

 

Chaz

 

Chaz,

most modellers use Brown to paint the ground cover.

Which, in my not so humble opinion, is WRONG.

 

Experience shows that soil in reality is more grey than brown

(yes, depending on the geology ! I know, there are red and even yellow, etc. ones).

 

So, "Grey with a Brownish tint" would be suitable.

And I think it is not so important whether it Light or Dank grey. Since most of it will

be covered with grass etc., anyway.

 

Regards

   Armin 

[chaz]

Chaz,

most modellers use Brown to paint the ground cover.

Which, in my not so humble opinion, is WRONG.

 

Experience shows that soil in reality is more grey than brown

(yes, depending on the geology ! I know, there are red and even yellow, etc. ones).

 

So, "Grey with a Brownish tint" would be suitable.

And I think it is not so important whether it Light or Dank grey. Since most of it will

be covered with grass etc., anyway.

 

Regards

   Armin 

 

And a lot of modellers paint tree-trunks brown - these are often grey, or even green.

 

The artist's maxim - paint what you see, not what you imagine you would see, in other words do the research.

[chaz]

I have a copy of Carsten's "Slim Gauge Cars" which I think is excellent. Does anybody know if there is an equivalent book of drawings of RR buildings? I know that drawings of depots, freight houses etc appear from time to time in the Narrow Gauge and Short Line Gazette but my collection of these is only recent and modest.

 

Chaz

[AJon30]

I have a copy of Narrow Gauge Pictorial Volume IX which features Rio Grande Southern right of way and Structures Rico to Durango which gives. at the back, some dimensioned drawings  One problem is that the narrow gauge buildings are built to "Standard gauge" sizes and are in many cases way too big to fit into the landscape.

 

Did you know that the NG&SL gazette is now out as a DVD? It is a slightly frightening 139.95USD but is probably cheaper (and takes up a lot less space than collecting all the copies of NG&SL gazette that I did!)

 

Rgds Andrew