I always get annoyed when people claim that BR▸ saved the Chiltern Line. No - they tried to close. Then they singled it.
Chiltern have had to spend millions.
The problem with the Chiltern line was it was hand over to the London Midland Region in the early 60's who saw it as a rival to the
WCML▸ , the Chiltern rejuvenation started in the mid 80's when it was handrd over to the WR / Network Southeast, I worked in WR maintenance at Paddington then and the state of the equipment on the Chiltern line was appalling in fact total neglect would be a better phrase even compared to the poorish state of the WR.