For the proposed East Coast Rail Link (ECRL) project, Central Committee of the Socialist Party of Malaysia, Sharan Raj proposed a tunnel under the Central Forest Spine (CFS) forest area.

"Contrary to popular belief, tunnels have the least impact on mountainous areas and ecosystems compared to paths on the surface," Sharan said according to MalaysiaKini.

https://www.malaysiakini.com/news/535330