You need to tell us what the railroad does.

Note sure what type of railroad you are looking for.  Yards vary depending on what they are used for.  Coal railroads used branchline yards to muster coal for instance.  One of more interesting of that type was Cane Fork.  It was a small yard with an engine facility but was a very interesting looking place so if you are interested in something like that Look up Cane Fork on the C&O.  

But if you want something else then you need to give a,bit more information about what type of railroad you want.

Google Earth

More info.

When you say "branch" are you referring to a small-sub for a Class-I railroad or a short-line railroad?

If Class-I, what would the yard be used for?  Example, staging area for a large industry such as coal, auto, etc.

Joe

Small Yard

Since it is a yard to be built in modules will almost never have the same function each time except for switching cars as it can be placed on a branch line for an Class 1 railroad at one meeting and the next time on a short line.
I want to build a yard which can cover different needs.
I know it's quite vague but it's not lie me on to something that can only be used specifically.

 "a yard to be built in

All you need to do is figure out how many tracks you want and how much space between the tracks and the module edges. To add some visual interest you could put a team track along the front edge and a freight house along the rear ........DaveB 

Small yard

Hi Hans - In my experience, small yards near a branch line junction are typically located on the mainline and not the branch itself.  An example would be Atlantic, Iowa on the Rock Island, and later Iowa Railroad and Iowa Interstate.  It served as home for locals that served nearby towns on the main, as well as the Audubon Branch (the remains of which were called the Atlantic Spur after the branch was cut back to just a 2-mile spur in about 1996).  

You can see a video of the yard as it stands today at  https://forum.mrhmag.com/post/iaiss-west-end-drone-view-of-my-prototype-12199818 , plus a schematic of how it looked in earlier IAIS and RI times further down in the post.  In the distance in the video, you can see Harlan Elevator, the lone grain elevator north of town that's one of three customers on the Atlantic Spur.

yard factors

What industries does the branch serve? How long are the trains on the branch?

Branch lines are in all

Branch lines are in all kinds, from a local line to connect a town to the greater rail network to vey busy mainline operations. In general, they are built-in lesser standard, lighter rail, lighter operation and smaller yards. Railroads did or still dont like to spend more money than necessary to provide service. On local lines, you will surprised how spartan the yards are! Maybe one or in some cases two passing tracks or sidings, a perhaps a spur to an industry but in most cases a team trck will do the job. Ypu never mentioned the time of period you are modelling, in old days the track in towns were spartan but in moderna times it is eve more streamlined to a just the mainline track. NAturally, the track arrangements are suited for the custumers and the service the railroad is to provide, if you are planning on a coal service, the yards to store the hoppers or condolas can be pretty big and big numbers of loads means a bigger lash up of engines, or even mallets in the steam days.  Today they serve usually one or two major customers so the roster of engines and freight cars are pretty much uniformal to this and passenger traffic is pretty much zero, maybe in the eighties or even a single RCD would do the job. So take alook on the railroads close by as here in Europe they does not vary that much in states, or else where overseas.  A branchline is a cool prototype for a railroad. The speeds are lower and as there is perhaps only one crew or train operating on the line the operation is perfect for a one man job. Besides as the trackwork is not to mainline standrards the train speed is lower and gives more sence of distance.

What you really want?

So what you really want is a generic yard that will fit in a space 12 ft long and 2 ft wide.  "Branch line", "main line" really doesn't matter.

It would be really helpful to know in which scale you are modeling.  That will actually determine how much you can fit.

The other thing that is critical to know is do you actually wish to do classification and switching in the yard.  If yes, then does the lead, the track the switcher pulls back on to switch, will that be on the modules or can it be on other adjoining modules?  If you use the other modules you will have to give up the use of the through track to be be the lead.

If the answer is not, you don't want to really do switching, then it changes the design of the yard.

As far as the engine facilities go, are you wanting a place to hold engines to be swapped out between trains or is it supposed to be a scenic element that is more someplace to have a bunch of detailed structures, but really won't be worked as an engine terminal?

Been there, done that...

https://model-railroad-hobbyist.com/node/39067

Assumptions

I am assuming that the yard will be in HO and be compatible with a Freemo layout since his website has pictures of Freemo set ups, but that's only a guess.

And that make a difference.

A Freemo set up might have low enough train density being single track in many cases that the main could be used as a yard lead, or that a "double track" module could be made single track with a yard lead.  On the other hand a typical double track "loop" set up would have a train passing by the yard every couple of minutes so would need a separate lead because the main would be occupied. 

If its a switching yard then they will want a siding or a couple long double ended tracks and could have several stub ended classification tracks.  If its a staging yard, then it would be several longer double ended tracks.  

One could build a diamond yard design with all long tracks the same length and then use it as a staging or class yard.  How you configure the throat is probably most important.  If its a Freemo set up then the main track is nearer the middle of the modules, that means that there can be longer double ended "sidings" (arrival departure tracks) on one side of the main and a class yard on the other, so there ould need to be a crossover from the main the sidings break from to the main/yard lead breaks from.

The "engine facilities" is also variable depending on what he actually wants to do with it.  If its supposed to be "scenic" with all the steam era bells and whistles and turntable, that's one thing.  If its supposed to be aplase to put power and then swap it out, a holding place for engines then something more modern would be better.  Maybe three or four tracks the length of their typical consist, with maybe one or two detailed to look like a afuel pad with maybe a sanding tower.  If they have the room maybe a one or two stall engine house, but that's not really necessary, it could be all open air, just as prototypical and way easier to manage.

You can see what I did ......

and use what works for you.  My branchline yard was originally going to be 14' x 2' but kind of grew to 16' long.  You can see why I needed to do that so you can address your needs before you start building

https://forum.mrhmag.com/post/southern-pacifics-jefferson-branch-12213647

Freemo/Modular

Yeah - being part of a larger modular set-up changes the game a little.

The original post used the words "small" and "branchline", which in most cases would probably NOT necessarily have any yard lead at all since the traffic volume would be so minimal there'd be no need to avoid the main. Just have a couple tracks, nothing needs to be fancy at all. But if the modules are ever combined with a show loop, then orbiting trains are constantly passing by the yard, and then a yard lead would be needed to avoid blocking (or being blocked by) traffic on the loop.