So there are so many people who want to convert their old 10 speeds into fixies and that really isn't hard.. But I actually have a track bike that I want to make into a usable road bike. Is it possible and if so how should I do it?

Six Fyx Conversion Kit | Fyxation

For $250 you could buy an older road bike

It looks like that is using something similar to the Problem Solvers track end to derailleur hanger adapter.

Problem Solvers Chain Tensioner W/Hanger > Components > Drivetrain, Brakes and Pedals > Derailleur Hangers | Jenson USA



Some might depend on your dropout spacing and whether you choose to cold-set the frame. If it is 120mm, you'll be quite restricted with the number of speeds you can use, even if you choose off-center rims.

It looks like it would be a pain to remove the derailleur every time the rear wheel is removed.

A few track ends have an integrated derailleur hanger, but it is rare.

Yup.

That addresses the issue of putting a derailleur on the frame. But keep in mind that true track frames are seldom drilled for mounting brakes, so you'll need to deal with that as well. Depending on what drill equipment you have available, you may end up needing to use nutted, rather than recessed Allen head fittings. And track frames tend to be pretty close-coupled, meaning brake reach may be an issue. Before you get out the drill, make sure you'll be able to find calipers that will fit the frame so the pads properly reach the brake track on the rim. Ultimately, as others have pointed out, you may find it more cost-effective to simply buy a used road bike instead.

Thanks CliffordK this is what I was looking for!

The spacing of the rear triangle for a track frame is much more narrow than a modern frame. I want to see it is the same spacing as 5 speed, I think.

Most track frames these days use 120mm OLD spacing; the same as vintage "10 speeds" with a 5-cog freewheel. Older (pre-1970s, mostly) track frames might have 110mm OLD spacing. But if this is a steel frame, it's not difficult to re-space it to accommodate wider rear hubs.

If you coldset the frame, then fewer single speed options later.

IF it has the capability of mounting brakes F&R as @JohnDThompson noted why not equip a 3spd IGH as was traditional on many British path racers pre-WWII?
Sturmey Archer even makes a FG/IGH, the S3X for the adventurous.

Note that many of us have perfectly usable FG and IGH machines that see considerable service in either configuration, properly equipped with brakes and foot retention like any road bike.
Which raises another point. Track bikes are designed for use on a Velodrome and make miserable road bikes with a lumber wagon ride on rough surfaces, twitchy handling and nervous descending.

As always, suit yourself.

-Bandera

I came here to recommend the S3X.

A true track bike will also be missing cable stops and guides.

I had this same urge a while back as well but took a different approach by using a track bike geo and had a road frame built around that.

As others have mentioned rear spacing of a track bike is 120mm. If you wanted to use modern gears you would need to have the rear spaced at 130mm. If you have a modern aluminium or carbon track bike that would be one major hurdle.

Another thing mentioned was cable stops. Problem solvers makes a bunch of clamp on options but they really do look nasty.

Then there is that thing called brakes. Since geared bikes have a freewheel you loose that ability to slow down the bike with your legs so hand brakes are sorta needed.

Track bikes aren't drilled for brakes (well at least the ones I ride) so you're going to have to either get those clamp on adapters for the front fork or hope you're really good at drilling. They have an option that straps the rear brake underneath the rear stays but like the cable stops, they just make the bike look nasty.

There's more to it than just begin able to bolt on a rear derailleur and at the end of the day you probably ruined a decent track bike and ended up with a meh road bike and probably spent more than just buying a dedicated road bike.

Internally geared hub?

Nashbar Cro-mo Road Frame

$100 and you have a place for RD, brakes, cables, etc.