China's national railway posted its largest ever annual cargo volume decline in 2015, according to reports from the Caixin news service.

In 2015, total freight carried by China's national railway fell 10.5 percent to 3.4 billion tons year on year, according to National Railway Administration figures.

The decline is the largest ever and does not bode well for its growth, which has diminished considerably over the past year, said Caixin.

By comparison, rail freight volumes dipped 4.7 percent year on year in 2014. Caixin said China is aiming to expand its rail freight volumes to 4.2 billion tons by 2020, which would require an average annual growth rate of around 4.3 percent.