Manono the largest ASX listed Tin deposit, page-9

Glad you raised this potentially devastating issue, no transport without railway sleepers.

But......Nigel even has this one covered.

Apparently one of the DRC rail companies is in the process of refurbishing their tie (sleeper) replacement machine. Cant recall exactly where it might be put to use though, on the rail line i guess. But i do recall Nigel mentioning it last week in Melbourne.