Redby did a shortened version of the 500 which replaced the Stagecoach 500 (that used to go to the Hospital), and it was a 3km+ loop.
https://www.flickr.com/photos/gjm-photog...6295923764

Then they replaced it briefly by a Taxibus TB500 / TB501 / TB502. 500 was as per above, whilst the 501 was the same as the S1 that they tried with Gateshead Central. And 502 went the other way around to the 501.

As for the TB300, very short lived. Ran from N Shields Metro via Minton Lane Estate (small estate behind the Parks Leisure Centre) before continuing along Howdon Road to terminate at the roundabout at Bridge Road (the one where you can see Meadowell Metro Station in the distance). Despite what things claim, it never went to Howdon, didn't even make it as far as East Howdon. Was a badly created route that could have been much more. It wasn't replaced by the 333. It was created due to the reduction in the 9A, and the 17/17A/317 whichever they were being called then being rerouted through the Royal Quays estate itself.
https://www.flickr.com/photos/gjm-photog...0746942143