These transactions, such as uncommitted transactions, are not deleted after checkpoint or after you back up the transaction log until the log-reader task copies the transactions to the distribution database and unmarks them. If an issue with the log-reader task prevents it from reading these transactions in the publisher database, the size of the transaction log may continue to expand as the number of non-replicated transactions increases.
Hi Basit,
The bit I've highlighted from the BOL extract is the important section. Essentially it won't matter how frequently you back up the TxLog, as long as the transactions are marked for replication they won't be removed and will continue to build up until the Log Reader Agent unmarks them.
That's why I'm saying, though what you've put in your article is correct and will clear out the transaction log (although I would still stay clear of truncating it!), it would be worthwhile mentioning that as a first port of call you should try to investigate the reason why the Log Reader Agent is not able to do its job properly. Otherwise the likelihood is you're only going to find yourself in the same position later down the line.