External Boilers

No.

How would you propose to get steam through the throttle and into the cylinders?

Rusty

In a word,,,,,,,no.

I.K. Brunel, engineer of the Great Western Railway in England, drew up general mechanical specifications for his original group of broad-gauge locomotives (7'-1/4" gauge) and received an assortment of engines of different designs that met the basic specifications, from five different English builders (ca. 1837). One builder's solution (Hawthorn, using a patent held by T.E. Harrison) was to put the boiler and the engine (and tender) on completely separate carriages, with flexible ball-and-socket steam connections between engine and boiler. Several problems made this design unsuccessful, including leaks in the flexible couplings and lack of weight on the driving wheels. In theory, however, a broken engine carriage could be swapped out, as could a damaged boiler. One of the two engines of this separated design, "Hurricane," had driving wheels 10 feet in diameter; the other used 6-foot drivers with step-up gearing to reduce piston speed. Brunel wished to reduce piston speeds as much as possible because of his concern with adequate lubrication and wear (no petroleum lubricants at the time).

Google "T.E. Harrison Hurricane and Thunderer" for a lot more information and some drawings on a variety of sites.