However, there were times that canteens proved economical.

After that woven polyester proved more economical than traditional flannel had been.

Whether shorter distances will prove economical as well has yet to be demonstrated, he said.

In some circumstances, it may prove more economical to replace complete joists.

The prototype proved economical in service as it used 10 percent less coal than the N class, but used 11 percent more water.

However, at higher speeds, a railway overcomes the barge and proves most economical.

But supporters of lease-purchase say the technique will prove more economical in the end.

Though Storey did not contribute much with the bat, his bowling proved very economical.

Originally using charcoal, modern methods use coke, which has proven more economical.

These saw blades, so far, have not been proven economical for cutting steel.