Are these two transformers the same?
I think the wording of your question is leading some readers astray.

You can indeed use two identical transformers to give the effect of a single centre-tapped transformer.  You would connect them like (assuming 120V/12V transformers):







simulate this circuit &ndash; Schematic created using CircuitLab

If the full output is zero rather than 24 volts, reverse the secondary connections on one transformer.

You can also buy transformers with dual primaries and dual secondaries - they can be connected as above, or with the primaries in series for 240V input.