The amount of lumber being moved through America's intercity rail system suggests a stronger-than-witnessed housing recovery could be just around the corner, according to London-based economics research company Capital Economics.

The volume of lumber being transported by railroad around the U.S. has a much closer relationship with housing starts, and it's currently pointing to stronger levels of homebuilding, said analyst Paul Diggle in a client note. Homebuilders may be stockpiling lumber in order to increase production.

The consultancy found a strong relationship between the volume of lumber shipped by rail and the number of reported housing starts. It contrasted that data pair to the relationship between lumber futures prices and housing starts, which it finds less closely related.

While lumber prices are currently depressed, the note states because lumber prices are also affected by other sources of demand and by supply conditions, it would be stretching the relationship to the breaking point to say that the current price level is pointing to weaker levels of homebuilding.

On the other hand, the rise in lumber volume chimes with the recent rise in homebuilder confidence and slightly stronger levels of housing demand, and points to further small gains in housing starts later this year.

U.S. homebuilder confidence, as measured by a monthly index of the National Association of Home Builders, was reported on Monday as being at the highest level since May of 2007.