These track lights are on their last legs, bases broken, directing light iffy.
IDEAL solution = simply purchase new fixtures, rip out old with pliers, pop new compatible ones IN.

However, Home Depot/others show NO tracks similar, only H J L.
If the photos don't read well, I would describe the guts as bare flat copper wires flanking the opening in the channel and no fancy holders ala the Home Depot images.

Do I want to take down the whole shooting match? May be the obvious choice, many will sell it as easier but .....
SIGH

I do love Lightolier .... maybe this? eBay shopping was suggested by an old pro.