A Burma-China railway and a stronger Allied war in China

What force could Britain support in China if Malaya were held and a Burma-China railway built?

Potentially Fourteenth Army, backed by a supply route that could strengthen Chinese forces and sustain more effective B-29 operations from China.

A secure rail supply route from Burma into China could potentially support Fourteenth Army rather than leaving Allied operations dependent on a thin air bridge. That formation could serve as a trained core around which Chinese forces improved organisation and effectiveness. The same route would deliver the supplies needed to sustain those armies and make B-29 operations from China more practical. Control of Malaya and Burma could therefore create a different Allied strategic geometry in which the war against Japan was pressed from the Asian mainland.