What kind of primer can be used on vinyl? I have tried both Model Masters and Krylon White Primer and both are not drying properly, after spraying primer it stays tacky, even after days of sitting in a room with A/C on.

Any suggestions on this will greatly appreciated.

It depends on the company of the tracks I think. I've used Krylon and Tamiya, both worked fine on some tracks. Others it would peel. I've used Citadel with decent results. Granted it's extremely expensive.

Tried the Krylon route and still ended up tacky.. i have the Pegasus's 1/18th 'The Great White Shark w/ Cage & Diver' and its an all vinyl kit and need to prime it

Several light misting of Tamiya primer will do
the job.

Make sure you have given your vinyl a good soapy wash.

Cheers,
Joe

In the process of removing the old primer with Goof Off, seems to be taking it all off and will have to give it a good wash and try that.

I'm not 100% sure if this helps as this is about spray can paints, but staying off enamel paints (at least for priming) with vinyl is a good rule of thumb.
Back in the day when I didn't know better, I painted some vinyl kits with enamels and some dried OK, while some stayed tacky.

You will be safe with Tamiya primer as it is lacquer based
and not enamel.

Again a few light mists so that there is bite for the
subsequent paint to stick.
Cheers,
Joe