Police said on Friday they had caught a 15-strong gang who bought, sold and used certificates to alter the 30-ton limit ofsemi-trailers to 48 tons so they could carry more goods.

Forty-foursemi-trailers using other vehicles' plates were seized along with a printer used to producevehicle identification numbers.

Police in Baoshan District said that in June this year they noticed a sudden increase in the number of 48-tontrucks with Heilongjiang Province plates.

Their investigation found more than 30 such trucks at several logistics companies in theYuepu and Luojing areas.

The vehicle identification numbers looked like they had been newly printed, officers said.

When the truck manufacturers were asked to check, they said they had not printed the numbers and suspected they were forged.

Police then traced a gang with members in other provinces. One surnamed Sun is said to have obtained plates and certificates of 48-tonsemi-trailers in Heilongjiangwhich were later mailed to logistics service providers Ma and Niu in Shanghai by two others,Zhang and Yang, fromHeilongjiang and Shandong provinces.

Another man, Li, is alleged to have used a special printer to print the 48-tonsemi-trailervehicle identification numbers to be used on those limited to 30 tons.

A 30-ton-load semi-trailer using a 48-ton truck's plate and vehicle identification number on the road

A 30-ton-load semitrailer with 48-ton plates

An alleged gang member points at 48-ton plates said to have been illegally bought, sold and used.