Light angle

Part of the answer is the angle of the "cone of light coming out of whatever you are going to use.  

How far forward will it shine and how high on the backdrop will it light?

Are you trying to light the front of the models on the layout?  Putting the lights 9" from the backdrop will backlight all the models in the front foot of the layout.

You also will have a lot of competing lights, the window, the room and the under the shelf.  There is a good chance that depending on the time of day, things will look differently, especially from a color balance.

"Are you trying to light the

"Are you trying to light the front of the models on the layout?  Putting the lights 9" from the backdrop will backlight all the models in the front foot of the layout." I don't have much choice as I have what I have. The front of the layout is already front lit by the room lights so I don't think that there is a problem. 

The situation is what I have so suggesting that it isn't ideal isn't really useful. As I said, I am asking for advice on the height of the shelf and the width.

Thanks for the reply, though.

See similar subject - my post is quite relavent

See   http://model-railroad-hobbyist.com/node/29429#comment-314415

Others have contributed much in same thread, but I'd suggest this as a basic start to re-illuminating an area.

My comment on Page 18 (!) is titled @Brian...

As practical answers,

if the geometry shown in your diagram is to scale, with a 10” shelf, the LED tape needs to be at the edge of the 10” shelf. The dispersion angle of LED tape light is 120 degrees. Draw a 120 degree angle centered just inboard of the edge of your shelf, in the drawing, and you can determine if light reaches the front edge of the layout.

As for height, try 18”. I recommend picking a height that satisfies your aesthetic for backdrop height and not worry about LED brightness. Anywhere from 18” to 24” you will be fine. Because your layout is small, you can always add a second parallel strip of lights at low cost. You could also use a different color temperature for the second strip and separately dim it to get different effects.

Thank you. That was the type

Thank you. That was the type of help I was looking for. Practical and relevant. Many thanks. I am off on Tuesday to buy the wood and the supports. I will order some LEDs on Monday so I should be able to try this out by mid-week.

I like the idea of two lines of leds. That could work well for me. Thanks also for the advice on the angle. 

Storage shelf above layout?

Murphy's Law being what it is, I would sternly suggest not storing things over the layout if you can help it.  But that's just my opinion.

Plastic scale models. I have

Plastic scale models. I have taken a lot of care of them, as well as the railroad, so either I will be foolish or my care levels will hold out

Strips, Tapes, etc

There have been considerable discussions of LED 'configurations' in previous post, and there are any number of names for these that can be confusing at times. Some refer to strips, or tapes, or .....

i recently ran across these 'tubular shaped shop lights' that are really flat strips/tapes mounted inside a tubular plastic shield/defusor. It almost looks like a old florescent tube, or even the LED tubes sold to replace the florescent ones.
 

Shop lite

This 'tube' inner structure hasa couple of plastic 'wings' that allow for downward dispersion of the light while blocking the very bright views directly into the light,....good.

One thing you might keep in mind is NOT mounting that under-deck lighting too close to the edge of the shelf, resulting in your looking at the bright light directly . Provide some sort of 'blocking' that still allows the source lighting to fully illuminate the lower shelf.

Here is another of their 'shop lites' I'm considering..
 

There are a couple of things I like about this fixture.
1) all the 'transformers are contained within the unit (no external power supply required)
2) linkable to one another, (power wise)
3 individually controllable on/off
4) can be screw mounted or hung by chain
5) fully protected LED's
6) metal 'blocking shield' over top

Mounting

That's why I referenced the "cone of light" and moved the lights inboard (9" rather than 10") because, depending on the fixture design the actual light source may be closer to the backdrop.  

I used tape LED's on a "shadow box" switching area, with only about 10" vertical clearance.  Its very bright.  The LED strip is inset about 3" from the front of the scene (which is about 10" deep).  The front track is backlit by the LED's.  There is nothing that says the LED's have to be mounted flat, they can be mounted at an angle.  That does two things it reduces the shadow/lighting difference on the backdrop (depending on the location, the mounting angle and the illumination angle of the LED's) at the expense of reducing the lighting on the foreground, with the added bonus that mounting at an angle tends to "hide" the lights from sight so that the viewer can only see the lights themselves from a low angle.

Note the color difference between Kentmere in the shadow box and Montchanin above it.  The brown boxcar on the front track at Kentmere is more backlit than the brown boxcar at Monchanin, or the boxcar on the track further back at kentmere, and the"shadow" on the backdrop about 3" below the top.  Since I am backed up to get a panoramic view and at a really low angle its fairly visible.  The average operator would be at a higher angle and closer to the scene, making the shadow less obvious.

LED on shelving

I wish I found this 3 years ago.  I have the old "tube lights" mounted on the outside of my shelves. (12 in shelves) layout at that point is 20+ inches deep.  Major shadow issues.  And also hard to work under..always afraid Im going to break one .

My upgrade is going to be some sort of extension for the shelving/overhead light to cast more lumens back into the models.