'Freezing' or waxing at cold temperatures - blocks filters causing fuel starvation. A number of Rail companies have found that these issues are causing damage to filters, engines and tanks particularly in Winter. The higher Cloud points and Pour points of Biofuels raise the Cold Filter Plugging Point (CFPP is the temperature at which fuels crystallise and block filter). Issues were seen on UK railways during the extreme cold of winter 2010. Delays due to 'frozen fuel'.

Cold flow information:

Filters - As with Microbial contamination, filters inevitably block due the crytallisation of paraffins at higher temperatures. This leads to fuel starvation.

Trace heating - Trace heating can be used to keep tanks warm (protect fuel from low temperatures). Can be used under certain conditions, however has proven to be extremely expensive. Trace heating, whilst increasing the temperature and protecting fuel from the cold, then acts as an incubator for Microbial contamination.

Inline dosing - Cold Flow Improver (CFI) additives can be dosed at storage tank level and vehicle level to protect fuel from low temperatures. It is important to note that even the best cold flow improvers cannot protect from extreme cold (-20C).