Guard rail for side of tabletop layout?

You could use clear lexan cut into six inch width strips and fasten it to the edge of the plywood with small screws with washers.

The lexan is a good idea - it allows you to see the trains, etc.

Such a barrier protects in another way: it keeps the hands of small visitors from getting to trains close to the layout edge, too.

One problem you can have is that if the track is really right next to the bench edge, the jut-out of passenger cars and longer locos as they enter a curve at the corners of your layout can hit a barrier flush with the edge.  Check first.  I've got about 30 feet on my layout including some wide curves that are right on the edge - the outer edge of the ballast is only 1/4 inch in from the bench edge, etc. For this reason I have never used a barrier.  I've run for seven years and only had one bad mishap where something tumbled over the edge - but that seriously (expensively)  damaged a Legacy steamer.

I have a lip of 1/8" plywood surrounding my layout. It's only half an inch or so high, just to keep small parts and whatnot from falling off, especially between the edge and the wall. However, you could bump it up to two or three inches of quarter-inch plywood and paint it in some way to blend with the layout. It might take some trial and error to find the optimum height that would prevent a locomotive from coming off without interfering with viewing. Alternatively, you could make a 1" wide railing of 1/4" plywood and elevate it a few inches on stanchions, which would be a bit less obtrusive and allow viewing by those barely tall enough to see over the table top. If you have the situation Lee describes above where a long car or locomotive hangs over the edge, you could just use a spacer to set the railing a little ways out from the table - the gap would have to be enough to clear the longest unit, but small enough that a car couldn't fall through it. 

Lexan is expensive, plywood is cheap (and easier to work with). 

I used 1/8" thick plexiglas on my 7' and 9' high, twin shelf 14x32 ceiling layout[now dismantled] at the Mountain Cottage. Lowe's scored and cut it into 4" strips on their big sheet cutter from a 4x8 sheet I bought. I just friction-fit it between two pieces of 1/4" moulding along the edge so I could easily remove it to lean over and work. You can also fasten it more permanently  to the raw edge of the 1/2" plywood and cover with screen mould, etc..

I'll second the plexiglass/Lexan suggestions.  I don't have a proper benchwork layout yet, but when I do, I've always been planning to go the transparent plastic route.

"In re-doing my layout, I found...it looked better on paper than in reality."

Amen to that, brother!

I read another post (can't remember which forum) where the writer used a solid rod (solid curtain rod?) mounted at the edge. Small wooden blocks 2" high attached to the edge every foot or so with the rod running through them. That would catch the train and be visually appealing....wouldn't it?

I haven't priced curtain rod but I'll bet you could buy it cheap at Goodwill.

If you have the aisle space, consider adding a 4" piece of decking plywood to continue the deck surface.

You could use small shelf brackets or angle brackets fastened to the side frame of the layout on which to mount the added decking.

Just adding lexon guards may not clear large overhangs of cars on edge mounted track.

I have a similar situation where I was worried about accidents.  I used lionel Girder bridges on the "front" side of my layout.  They look nice (picked some cool milwaukee road road ones) and actually prevent accidents. Plus 1 bridge gets quite a bit of coverage because you have each half of the bridge and you can space them out a bit. On the back side I used more a more affordable wood fence.

The front of my layout has a 1x4 fascia that is about 1" above the level of the table.  It has a routed edge on top to give it a finished look.  It serves as a very effective guard rail.  On my child hood layout, my father fashioned brass brackets in an "L" pattern with a second piece bent and held by a small brass bolt and nut to the base "L".  He then had quarter inch by one inch lathe pieces of good quality wood cut that were held in place by the brackets.  He even modified the center bracket slightly so it would serve as a lock, thus the guard rail would not slide in the brackets.  On my 5x9 table there were two "rails" on each side and one 5' "rail" on each end. Each piece was numbered so I always was able to put the "rail" back into the same spot.  Whenever I wanted to work on the layout, I would remove the "rail" and thus had easy access to it.  The design was so good and so easy to duplicate, that, as an adult, when I built my first layout in my home, incidentally a much larger one, I made more brackets and "rails" than those on hand from my childhood days.  I would have followed through on the design for a third time, except this time I was striving for a finished "furniture" look. 

Hope everyone had a good summer and fall.  It's raining here, we might have winter which means back to the trains. 

I built this with a small lip and it worked fine, if you are right up next to the edge then maybe a little taller would help.  I know this would be within reach of kids, It's all conventional, basic Lionel nothing really collectable in my set up.

 

I have a portable door layout to that I use to demonstrate the windups, and it has 6" lexan guards on the ends, basically what Trainman9 described.  This video shows the layout in action; there is a derailment between 2:05 and 2:25 that shows why I have the guards:

I'm in the same boat. My first layout since I was a kid. What I did was attach 1/4 - 3x3 poplar board (which is pretty light) and the glued a 1/2 piece of molding to finish it off. It's still in process as you can see. I may add lexan or some type of guard rail in the future.   

Lexan is expensive, plywood is cheap (and easier to work with).

If you live anywhere near King of Prussia PA I have about 40 feet that you can have for free. Brand new, still has the protective paper on. I think they were cut to about 6-7 inches.