...and even then, it'd barely make it to the disaster site before everything had already gone pear-shaped.
I mean, what was the point of having both TB1 and TB2 in the original series? TB1 could do Mach 22 (according to the usual sources), but could do little other than set up a command post on arrival. TB2 was much slower, capable of no more than 5000 mph, with 2000 mph being the 'official' cruising speed (again according to Prof. Bing O'Google). So, unless the disaster in question was taking place very slowly, or within several thousand miles of Tracy Island, most episodes would consist of TB1 turning up, Scott Tracy saying "Hey Thunderbird 2! Hurry up!", followed by everyone dying spectacularly thanks to Derek Meddings and his exploding models.
The rebooted series actually does a much better job of this, as well as fixing the glacial pacing and excessive padding in the original. Someone clearly sat down and thought rather more of this through.
(A much clearer illustration of the problem with some of those Gerry & Silvia Anderson shows is "Joe 90": that show is basically built on truly horrific child abuse. How the hell that ever got as far a pitch, let alone commissioning, I've no idea.)