Rohan,
Only RCF Kapurthala has the technology to build LHB coaches end to end, and off late they are sending some shells to Rae Bareli for furnishing after primary manufacture. ICF is not capable of making LHBs which makes half the capacity not available for LHBs. Also RCF has to make conventional rakes for replacement of older rakes. So effectively only 60% of its capacity goes towards making LHBs. However this year there is a really SIGNIFICANT increase in the LHB production plan, and Poorva and Purushottam are being converted to LHBs. This should be a good start. I believe some new trains announced may also have LHBs to start with looking at the production plan. So lets hope they do it...
more... quick and also bring up the shell plant at Rae Bareli which is still under construction. Of course our block level party veteran RM may not be v interested to speed it up!!