Tight radius

You hit on the main problem. A 4x8 layout in HO has to have tight radius curves and modern equipment has a tendency to derail on tight curves, thus no one does it.

There are 3 solutions as I see it.

1. Keep the 4x8 size, but switch to N scale and you can model modern era.

2. Keep the 4x8 size, but model transition era or earlier.

3. Switch to an around the room layout and model modern.

Plan 3 would require either a point to point trackplan OR some sort of duck under / lift out / swing bridge or some such at the entry point.

Or split the 4x8 in half....

Take a 4x8 split into to two 2x8 and make a L shaped layout.   You can tweak most 4x8 layout plans to fit that and get a much improved layout, IMHO.  Also easier to expand shouls you want to

Shelf layout

Will said it. Plan #3. With a lift or gate at the entrance it will satisfy all the requirements for a ton of fun.

It doesn’t have to be. 4 by 8

You could actually fit a 5 by 9  in such a room and have 36 inches of access on all sides. Such a layout would accommodate 28” radius which would handle most modern cars up to 70 foot length easily enough, maybe longer.

You mentioned having two spare bedrooms. You could use one just for the layout and the other for a workbench, storage shelves for rolling stock, supplies, books and mags, armchair railroading etc.

Barry P

an 11 by 12 foot room

would be perfect for an HO scale around the walls shelf layout. Corner radius could be large enough for modern equipment and switching and passing tracks could be placed at various spots around the loop. It's not too hard to make a removable or lift up section for the room door and with the right track plan the layout could be operated point to point with the door section removed most of the time. If you keep the benchwork relatively norrow you'll still have plenty of space in the middle of the room for operators ,and if you build the benchwork high enough you can place workbench and other furniture against the wall under the layout. I have a TT scale layout in a similar sized room and it's quite satisfying to work on and operate, and my grand kids can still sleep in there on blow up mattresses when they visit......DaveB

Prototype

Also picking the right industries can help a small layout.

Aggregate and cement shipments usually ride in shorter hoppers and covered hoppers, some aggregates are move in ore jennies (or "OJ's" as the SP called them in Texas).

Acids are in small tank cars.

Most coil cars are 50 ft or shorter so a company that uses sheet metal might be a good one.

Keeping with the Texas theme, drilling mud or frac sand rides in small cars.

TOMA

I think you should use the TOMA approach.  You can use the search box above (enter TOMA) to find articles and threads. 

Basically you build a small module typically 2x4 add track, wiring, structures, and scenery.  Once finished, build the next one and hook it on, and so forth.  You could also have 1 or 2 modules with just staging on one or both ends of the finished module(s) ( and move them out as you add finished modules).

This approach allows you to build a little at a time at your own speed.

Good luck

Paul

4x8 Alternatives

Check out Byron Henderson's 4x8 alternatives.  https://www.layoutvision.com/why-waste-the-space-on-a-4x8

Scott Perry's HOG/Better Beginner's Layout

When I see posts like this, I always recommend a hard look at Scott Perry's HOG layout. (Rick Wade here on MRH has also done a layout based on this plan.  https://forum.mrhmag.com/journals-was-blogs-891775) It takes roughly the same area as a walk-around 4x8 and has the same surface area, but much broader curves and operating potential, while being easier to scenic.

http://hogrr.blogspot.com/

Mike in CO 

Test Equipment & Curves

Hi Armchairhobbyist,

Test your largest loco and freight/passenger cars on different curve radii until you determine the reliable minimum for operating, coupling and uncoupling...it might help you generate a solution regarding the corners of your layout.

Once you know the minimum reliable radius, designing the layout will be easier and more satisfying.