If they are it would be a real shame - I understand the economics due to replacement etc but at what stage does a heritage rail stop being a heritage rail? If concrete is used then the only thing heritage will be what’s running on the lines
You'd better not go near PBR with ideas like yours sonny, otherwise the NA's will have to lose their steel cowcatchers and replace them with timber; their remotely mounted grease nipples will have to go; so will the turbo generators and electric lighting to be replaced by kero lanterns, and 14A will have to have its all welded boiler scrapped and replaced by one with riveted construction.
While you're there, you might care to tell the shop at Belgrave station that the electric freezers and refrigerators have to go, as do the fluorescent lights and electronic cash registers.
The front end loader that coals the locos will also need to go, and the workshop's electric power will be replaced by steam-powered shafts, belts and pulleys to drive the machines.
Need I say more?