The Baikal–Amur Mainline (,,, ) is a broad-gauge railway line in Russia. Traversing Eastern Siberia and the Russian Far East, the -long BAM runs about 610 to 770 km (380 to 480 miles) north of and parallel to the Trans-Siberian Railway. The Soviet Union built the BAM as a strategic alternative route to the Trans-Siberian Railway, seen as vulnerable especially along the sections close to the border with China. The BAM's costs were estimated at $14 billion, and it was built with special, durable tracks since much of it ran over permafrost. Due to the severe terrain, weather, length and cost, Soviet general secretary Leonid Brezhnev described BAM in 1974 as "the construction project of the century". If the permafrost layer that supports the BAM railway line were to melt, the railway would collapse and sink into peat bog layers that cannot bear its weight. In 2016 and 2018 there were reports about climate change and damage to build
La línea principal Baikal-Amur (,,, ) es una línea de ferrocarril de gran alcance en Rusia. Atravesando Siberia Oriental y el Lejano Oriente ruso, el BAM de larga duración corre entre 610 y 770 km (380 a 480 millas) al norte y paralelo al Ferrocarril Transiberiano. La Unión Soviética construyó el BAM como una ruta alternativa estratégica al Ferrocarril Transiberiano, visto como vulnerable especialmente a lo largo de las secciones cercanas a la frontera con China. El costo del BAM se estimó en 14 mil millones de dólares, y se construyó con pistas especiales y duraderas ya que gran parte de ella corrió sobre el permafrost. Debido al terreno severo, el tiempo, la longitud y el coste, el secretario general soviético Leonid Brezhnev describió el BAM en 1974 como "el proyecto de construcción del siglo". Si la capa permafrost que apoya la línea BAM se derrumbó, el ferrocarril se derrumbó y se derrumbó en una capa de pe