Train from train from Liujiang to Zhangjiajie

We are planing overnight train from Guilin to Zhangjiajie. But I was told that train from Liujiang to Zhangjiajie is the worst train in China now. The train condition is not very good including sanitation condition. Is it true? And if so what are the other possibilities to go from GL to Zhangjiajie?

Thank you!

Alla