You're gonna love this.
As part of moving toward the future and all that jazz, Microsoft have started phasing out some of their older stuff to make way for the new (ask me, they no longer properly support Win95
).
I believe starting with WinMe they've been working to cut out MS-DOS - probably a good idea, since building a 32-bit operating system on such antiquated underpinnings has always been a pursuit of questionable logic. Anyway the short answer is, WinXP is totally rewritten from the ground up - not an ounce of DOS in it. TrackEd2 runs if not totally under DOS then in a DOS-box under Windows. No DOS means those programs you used to run under DOS have a big question mark hanging over them as to whether you'll get them to run on WinXP (though I'm told backwards compatibility with programs from previous versions of Windows is good).
Any ideas, hmmm. Unless you can trick TrackEd2 into running under Windows, which you probably can't since it needs the DOS environment, you may have to go as far as installing an old copy of DOS (if you can find one) on your machine and running it as an operating system in its own right, or under WinXP if it will let you, or go for something like a DOS emulator or something. Brr, I'm scared already. As for a new version of TrackEd2, TRI wrote the original TrackEd2 and I doubt they'd be up for it.
I think we have Windows-based utilities now that can do most of the stuff TrackEd2 did, maybe you could try some of those. Like Tikis Truckshop, f'instance.