All RTKs property asssets were ring fenced to provide funding for the rail network.
Every single penny in land and buildings which could have been realised was not available to RTK save for investing in the network. In the event of capital profits these would cause one off cuts in the subsidy. Revenue profits were estimated by the rail regulator and knocked off the annual payment. So if RTK sold anything there was almost no benefit to either RTK or the network!
When Major set up the structure he tied RTK up like a turkey waiting for the oven. The only way to increase profitablity was short term cuts in maintance and distribute as much cash by dividend ASAP. Both those factors eventually being the justification for the current government to kill RTK.
Its obviously sad, but if you read the original prospectus the "Ring fencing" was put in place so as to ensure that RTK would always be a basket case depending on HMGs charity. HMG simply stopped being charitable post Hatfield.