Other than in the coalfields of China, the steam locomotive had vanished as an important mover of goods and people by the closing years of the last century. The end was remarkably  and in this book's view  unnecessarily swift. Britain was still building steam engines in 1960, and yet only eight years later the last of them had been withdrawn from service. In some countries (the US is the leading example) the end came sooner; in others such as India and South Africa, it was protracted into the 1990s.

They didn't, of course, vanish entirely. Hundreds, perhaps even thousands, of them have been preserved by museums and heritage railways and are regularly steamed for cross-country excursions (living close to a main line in London, I sometimes hear their whistles). But they exist as treasures; probably there is no other mechanical object that has attracted such devotion and delight, or whose passing has caused such mourning. For every man of a certain age who remembers 1968 for the Paris insurrection (bliss was it in that hour  or not) there must be another three or four times that who remember it as the year British Rail marked the end of steam with a special over the Settle and Carlisle line. Double-headed by a pair of Black Five 4-6-0s, if I remember correctly.

Out of this enthusiasm has come a literature. Men of a certain age, including this reviewer, have been glancing at books titled Giants of Steam (or something very like it) since they were first lifted up against a fence and told by their daddy to wave at the driver. They were  are  stimulating books of their kind: pornography for the steam lover. "The Midday Scot hauled by Stanier Pacific City of Salford picks up water at Tebay troughs on a bright November day in 1953" would be a typical caption, and a sky filled with smoke the upper half of a typical photograph. But this isn't really that kind of book  the title does a disservice to Glancey's account of the last great steam locomotive engineers and his intriguing argument that it was fashion rather than reason that killed steam locomotion, at a time when its technology was poised to make a great leap forward, or at least had many years of economically useful life still to run.

Just as the sailing ship adopted its speediest and most graceful form, the clipper, in the shadow of steam navigation, so the steam locomotive had its most innovative period after the combustion engine began to compete for the railway's traffic on the roads and in the air. In Britain, Sir Nigel Gresley and Sir William Stanier are the names most remembered. It was Gresley's streamlined Mallard that in 1938 took the world speed record (125.88mph) for a steam locomotive, which still stands despite the rival, though less well-supported, claims of Germany and the US. Stanier, too, designed powerful streamliners for the Anglo-Scottish trade  his took the hilly west coast route while Gresley's took the flatter east  and, though he never quite achieved Gresley's fame, his elegant 1930s designs settled the look of the British engine till the end of its days.

Borrowing Myles na Gopaleen's phrase "steam men", Glancey confers on this late breed of loco engineers the decency and dignity of the modest hero, and perhaps there is something heroic (the Knights of the Round Railway Turntable?) in their determined quest to make the steam engine faster, stronger and more fuel efficient, as the threat of diesel and electric traction gathered on the horizon. Britain had a radical in Oliver Bulleid, who designed for the Southern Railway what is almost certainly the ugliest steam locomotive of all time, but by the second world war most British steam engineering was conservative when compared to the innovations coming out of France, Germany and the US. British engines looked very good, concealing their mechanics inside smooth shapes, but it was foreign engineers such as France's André Chapelon who stood the best chance of giving steam locomotion a future.

Chapelon adopted what Glancey calls a holistic approach to thermodynamics. First, he made sure that steam flowed through the circuit of boiler, cylinder and exhaust as freely as possible, minimising any obstructions. Second, he used the same steam twice by admitting it from high-pressure to low-pressure cylinders, a process known as compounding. Neither technique was unknown in Britain, where most marine engines and even some locomotives had been compounded since the 19th century, but Chapelon's machines reached new levels of sophistication (which to the British mind meant unreliable complexity) in a French railway culture that gave a train crew long-term charge of a particular engine; in Britain, a driver might be at the controls of Mallard one day and Kingfisher the next. The result, Glancey writes, were lovingly cared-for locomotives that "ran like silent sewing machines", equal in acceleration and tractive effort to the first generation of diesels and electrics.

No steam engineer really doubted that electric power would eventually triumph. The more debatable question is the extent to which diesels were needed as a stopgap between one power source and the other, because the steam locomotive is a robust machine and whole fleets of them met too early a death. Glancey refuses to blame oil lobbies and conspiracies, even in America. The diesel industry, he writes, was "young, fuelled as much by new business management techniques as by oil, and a rapier in terms of sales and marketing to the steam industry's broadsword". In 1945, diesels worked only 8% of America's train passenger miles; in 1948, the figure was 34%; in 1960, the Norfolk & Western withdrew America's last steamers from regular service.

In Britain, the key word in the late 1950s was "modernisation". Steam locomotives, like the Euston Arch, looked old  off with their wheels! Can they ever make a return? Glancey thinks so, given that there's more coal than oil left in the ground and that a new breed of engines could be even more thermally efficient than Chapelon's. But it isn't yet time, I think, to dust off the Box Brownie and return again to the spotter's position at the platform end, to await the Scotch Express.

 Ian Jack's The Country Formerly Known as Great Britain is published by Vintage.