Bangkok Grey Line Monorail

The Grey Line is a proposed monorail line in Bangkok by the Bangkok Metropolitan Administration (BMA). The Grey Line would provide another north-south route connecting the northeast suburbs to central Bangkok.

The first section that has been proposed is the 19-kilometre segment from Watcharapol to Thong Lor. This begins in the north at Watcharapol Station on the Pink Line, then south to connect with Lat Phrao 83 Station on the Yellow Line and and Ramkhamhaeng 12 Station on the Orange Line, crossing the Light Red Line (Bang Sue–Hua Mak) to Thong Lor Station on the BTS Sukhumvit Line.

The second section has been proposed to run from Phra Khanong to Rama III. Phra Khanong is two station away from Thong Lor on the BTS, so it’s not apparent if they mean to somehow build a monorail line adjacent to the BTS, of if they are building two separate lines and calling it one line. Previous plans show the monorail running down Thonglo (Sukhumvit 55), which would be the most logical way to continually run the line.

The final section would run from Rama III to Thaphra on the Thonburi side of the Chao Phraya River.

In November 2021 the BMA announced that a feasibility study would be completed by March 2022.

Links And Resources

BMA Grey Line Monorail – news and discussion at Skyscrapercity.

Bangkok Mass Rapid Transit System Guide.

Maps

[Map of Grey Line Bangkok.]

[Via Origin.]

News Archive

2025

MRTA to speed up bidding on four lines – [14/08/25]

“The BMA conducted a partial study of the Grey Line and the Silver Line but the MRTA will undertake an updated feasibility and environmental reviews to reflect current conditions”.

“The 27.85-billion-baht Grey Line is a 16.25 km route with 15 stations.”

2023

BMA wants MRT to take over remaining mass transit projects – Governor – [22/11/23]
“The projects, currently being studied and to be implemented by the BMA, include the Grey Line monorail train service between Watcharaphol and Thong Lor”.

2022

BMA starts courting Grey Line investors – [18/03/22]
“The Bangkok Metropolitan Administration (BMA) is seeking private companies interested in investing in its Grey Line monorail project as construction is due to begin in 2026.”

2021

Plans for new ‘Grey Line’ gather steam – [13/11/21]
“The Bangkok Metropolitan Administration (BMA) plans to complete the feasibility study and conduct public hearings into the construction of the first 16.5km section of the Grey Line electric monorail project in March.”

City Hall hires consultants to oversee new monorail – [09/08/21]
“The Bangkok Metropolitan Administration (BMA) has hired consulting firms to provide analysis ahead of a public-private partnership (PPP) for the capital’s new monorail project.”

2019

The upcoming mass transit “Bangkok’s Monorail Grey line” – [Dec 2019]

Bangkok’s Grey Line gets green light, but will Thong Lor property market benefit? – [30/09/19]

Bangkok transit map to feature new Grey Line – [30/09/19]
“The Grey Line is a new monorail project linking Vacharapol in northern Bangkok with Thong Lor in the Sukhumvit business area as well as Lumpini Park with the Tha Phra area in Thon Buri.”

2018

City Hall seeks to revive Grey Line project – [15/06/18]
“City Hall has called for a revival of the first phase of the Grey electric monorail train line project from Watcharapol to Thong Lor following its failure to gain approval from locals living along the planned route and an unsuccessful environmental impact assessment.”

2015

BMA holds public hearing on Grey Line monorail project – [21/01/15]
“The Bangkok Metropolitan Administration (BMA) has held the second public hearing on the study of the Watcharapol- Rama IX Bridge – Tha Phra Grey Line Monorail construction design project.”

There and back on a single, narrow line – [10/01/15]
“The latest idea is the proposed construction of the “Grey Line” monorail which will link Watcharapol and Tha Phra via Rama IX.”