If the frame is steel, then sure. Google "track dropouts", and there are several styles of replacement weld-on track dropouts to choose from for your rig. I believe they're anywhere from $30-$70, and if you're a good welder & can put down a good bead, you should be ok as long as the angle of the dropouts is correct during the welding process.
If you ride freewheel, an easier option to switching dropouts on a vertical-dropout frame is to use a derailleur as a chain tensioner. I have vertical dropouts on my rig, and I used to use a half-link chain, but still had chain tension issues. After hearing about some people having trouble with the durability of a traditional chain tensioner, I decided to try and use my derailleur. 2 years later, it still works great, and if i add or drop a few teeth on the chainring it's not an issue at all. just set the limit screws, and youre ready to go! Hope this helps.
EDIT: or you could try a White Industries ENO eccentric hub for your rear wheel. Once you have the wheel bolted into the frame, the axle rotates, and in turn increases chain tension. They work with any regular freewheel, and I believe the hub starts at about $135 USD.



















if it is steel, yes, you can put track dropouts
it is worthy? only you can anwser that.
Rik
Berlin Bike Polo 2010
London Bike Polo 2008 - 2010