bryan275:
I can see where you are coming from, as the Americans would say.
Let us start with the speed of diesel trains. Such trains are, in principle capable of even higher speeds than the InterCity 125; this has been shown in numerous tests. But in practice, who actually runs diesel trains at high speeds? The InterCity is an exception, and, as you note, it holds some sort of world record. Still, compared to really fast passenger trains, it would be considered something like a "medium-speed" train. (Who else is running diesel trains at anything approaching that speed?)
You also state that:
The funniest bit was suggesting that cargo is not time sensitive.
He did not suggest that. What he suggested is cargo is not as time sensitive as passengers, which is an entirely different statement. And he in support of that, he gave an argument that seems easy enough to verify: look around the world; who is moving train cargo at really high speed? As far as I can tell, even where countries have high-speed tracks and trains, cargo tends go to much slower. In Japan, for example, the railway lines are operated on the basis of "speed for passengers" and "predictability for cargo"; and the two generally travel on different lines.
Lastly: I see no basis for the charge of
ukabila. A case of "your name betrays you"?.