 They reached their peak in steam locomotive boilers, where the complexity of a syphon was justified by the need for a compact and lightweight means of increasing boiler capacity.One of the best-known forms for locomotives was invented by the English locomotive engineer who received a US patent.The Nicholson form combined a complex shape that provided more heating area in a given space than did the earlier tubes and funnels, yet was simple to make, being folded from a single sheet of steel.