Two heavy steel truss bridges in Bukit Timah - opened in 1932 as part of the former Keretapi Tanah Melayu (KTM) railway line - have served as landmarks for decades.
For passengers, the structures meant that they were at the halfway point of their journey through Singapore from Kuala Lumpur, and for motorists, it marked the 7th and 9th miles of Bukit Timah Road.
On Monday, the Urban Redevelopment Authority (URA) said the bridges will soon be gazetted for conservation. They will join the ranks of other conserved structures such as the iconic bandstand in the Botanic Gardens and the Cavenagh Bridge next to Fullerton Hotel.
The bridges comprise a 45m-long one across Bukit Timah and Dunearn roads near the defunct Bukit Timah Railway Station, and a 60m-long one near the Rail Mall in Upper Bukit Timah Road.
The URA described the bridges as "endearing local landmarks" that capture Singapore's railway heritage and provide seamless connectivity for Rail Corridor users.
On Monday, the URA also unveiled the winning concept masterplan for the Rail Corridor. The plans included design solutions for the two bridges, to facilitate safer crossings for different users.
Designed by Singapore's United Engineers, the bridges were built as part of a realignment for a more direct route into the city centre.
Architectural historian Lai Chee Kien said the Bukit Timah and Dunearn roads bridge replaced the original line as it was often flooded.
The heritage community welcomed the move to protect the bridges. Dr Lai said they are essential to the Rail Corridor's continuity.
Singapore Heritage Society exco member Yeo Kang Shua reckons the upcoming gazette shows that industrial heritage is also gaining recognition. "Bridges are important both physically and metaphorically."
Elaborating on his personal memory of the bridges, heritage enthusiast and naval architect Jerome Lim said they signified his return to Singapore in the early 1990s when he travelled up to Kuala Lumpur to visit his Malaysian girlfriend, who eventually became his wife.
"The bridges were something I looked out for because it meant that I was reaching home," he said.
"The 7th-mile marker was where the Yeo Hiap Seng drink manufacturer's factory once stood and it was where a passenger could see right through the squatter shacks which were very close to the tracks by the factory."
Dr Lai said that Bukit Timah used to be home to many industries which were served by the railway, including Tien Wah Press, Hume Industries and the Ford Factory.
Heritage experts also raised the importance of conserving a similar steel truss bridge structure across Sungei Ulu Pandan at Clementi which used to be part of the rail's Jurong line.
Heritage enthusiast and blogger Mr Lim said much of that line, which was built in the 1960s, has been dismantled or is at risk of being erased. He said: "It is possibly the largest and most visible structure from the Jurong line. It was an essential component in the development of Jurong Industrial Estate."