But bear in mind that is if you draw no 5V and 3V loads and discounting the efficiency of your PSU.
This is corect from a mathmatical perspective - but there are a few ways that companies state the power of their PSUs. You would be best to look at the power information on the side of your PSU which will outline the power per line (3V, 5V 12V). Then do the same math for the 12V to ensure you are not making too much of a leap.
From the link - you can find information on each 12V rail - one is 23 Amps the other is 20 Amps.
Also - this is one of those companies that states all the power coming out as a total.
But bear in mind that is if you draw no 5V and 3V loads and discounting the efficiency of your PSU.
It's physically impossible to get 60A out of the combined +12V rails of the TR2-600NL2NC.
The +12V maximum continuous output current will vary between 38.7A to 43A depending upon the load placed on the combined +3.3V and +5V rails. You need to look at the PSU's cross loading graph.
"no 5V and 3V loads" is completely unrealistic.
PSU conversion efficiency is completely irrelevant in determining maximum combined +12V output current.