Chiang Rai Double-Track Railway Passes 50% Completion

CHIANG RAI – The State Railway of Thailand (SRT) has shared a fresh construction update on the northern double-track railway project for the Den Chai, Chiang Rai, Chiang Khong route. Work is moving forward as planned overall, with civil works now past the halfway mark.

SRT says it’s pushing contractors on every contract and still targets an opening in 2028. The line is expected to support freight transport, tourism, and border trade, while strengthening northern Thailand’s rail connection to the Mekong region.

According to SRT, the Den Chai, Chiang Rai, Chiang Khong double-track railway covers 323 kilometers, with a construction budget of 72,835 million baht. As of December 2025, overall progress reached 50.496%. That is just 0.237% behind the plan, mainly due to flooding in northern areas. SRT says the delay remains manageable, and the 2028 service start date stays on track.

Construction Contracts, Progress by Section

The project is split into three construction contracts:

• Contract 1 (Den Chai to Ngao) covers 103 km with a budget of 26,560 million baht. Progress is at 47.618%, which is 7.406% behind plan. This section was hit harder by flooding, and the terrain is more challenging, requiring multiple structures and track works across many points. SRT says it is monitoring the situation closely, adjusting plans, and speeding up work.
• Contract 2 (Ngao to Chiang Rai) covers 132 km with a budget of 26,890 million baht. Progress is at 56.726%, which is 4.136% ahead of plan.
• Contract 3 (Chiang Rai to Chiang Khong) covers 87 km with a budget of 19,385 million baht. Progress is at 45.798%, which is 3.520% ahead of plan. This segment is key for extending rail access toward the border area to support future freight movement and cross-border trade.

Tunnel Work Update: A Major Part of the Project

Tunnel excavation remains a central part of the Den Chai, Chiang Rai, Chiang Khong rail project. SRT reports the following progress:

1. Song Tunnel (Phrae), 1,059 meters, 55.95% complete
2. Ngao Tunnel (Lampang), 6,211 meters, 69.30% complete, the longest railway tunnel in Thailand
3. Mae Ka Tunnel (Phayao), 2,700 meters, 69.25% complete
4. Doi Luang Tunnel (Chiang Rai), 3,400 meters, 64.79% complete

SRT says tunnel work is still following the plan. Three of the four tunnels have already reached a breakthrough. The remaining one, Ngao Tunnel, is scheduled for breakthrough on December 12, 2026.

Still Targeting Service in 2028

SRT notes that some contracts have slipped behind the original schedule, but the project as a whole has already passed 50% completion. With continued acceleration across all contracts, SRT says it remains confident the Den Chai, Chiang Rai, Chiang Khong double-track railway will finish and open within 2028 as planned.

Why the Den Chai, Chiang Rai, Chiang Khong Rail Line Matters

This double-track railway is one of Thailand’s major transport infrastructure projects. The route begins at Den Chai Station in Phrae and runs through 59 subdistricts across 17 districts in four provinces: Phrae, Lampang, Phayao, and Chiang Rai.

Once completed, the line is expected to improve passenger travel and freight transport. SRT estimates the train trip could cut travel time compared with driving by about 1 to 1.30 hours.

The route is also designed to strengthen economic links from northern Thailand to the Thailand-Laos border and the wider Mekong region. It should support border trade and cargo transfers headed to Laem Chabang Port, while helping lower overall logistics costs.

At the same time, this railway line is expected to attract travelers. The route passes mountains, bridges, and multiple tunnels, with natural scenery along the way. SRT expects that increased rail travel could help boost tourism and create more income for communities along the corridor.