MOSCOW, Nov. 26 (UPI) -- Experts said the buildup of sand that has caused small sandstorms when trains arrive at Moscow stations may have been caused in part by soundproofing efforts.
Passengers at the Belorusskaya, Kievskaya, Chistiye Prudy, Sukharevskaya, Trubnaya, Rimskaya and Ploshchad Ilyicha stations said sand buildup at the stations has recently become so heavy that they often find themselves wading through large piles of sand and are sometimes hit with sandstorms when trains pull in, The Moscow Times reported Friday.
Some experts said the sand may have been building up in ventilation systems for years and was brought to the main areas of the stations by work to soundproof train lines running beneath the renovated Bolshoi Theater.
However, others said many of the sandy stations are distant from the theater and the sand was likely brought in by repaving efforts on Moscow streets during the summer.
"A lot of sand was brought into the city center, and it could have easily gotten into metro's ventilation shafts," said Alexei Klimenko, a member of Moscow's chief architect's board of expert-consultancy.
Mayor Sergei Sobyanin said the ventilation system for the underground trains will be replaced within the next three years.