The Willy the Wizard title in question is a 36-page illustrated book; it has a website, with extracts apparently chosen to highlight the claimed resemblances such as "Strange Eye Wizard", "Wizards Prisons", "Wizard Goverment" and "Wizard Trains".
As to Wizard Trains, Ansible asks "did Jacobs nick the train concept from Susan Cooper's Silver on the Tree (1977)?" Actually you can track the magical train motif even further back, particularly to Lord Dunsany's Edge of the World mythos, where the magical lands bordering the edge of the world can be reached by train from London by getting a special ticket:
So Neepy Thang set out. He bought the purple ticket at Victoria Station. He went by Herne Hill, Bromley and Bickley and passed St. Mary Cray. At Eynsford he changed and taking a footpath along a winding valley went wandering into the hills. And at the top of a hill in a little wood, where all the anemones long since were over and the perfume of mint and thyme from outside came drifting in with Thang, he found once more the familiar path, age-old and fair as wonder, that leads to the Edge of the World.
- The Bird of the Difficult Eye, Tales of Wonder, 1916
The ways to that town are winding; he took the ticket at Victoria Station that they only give if they know you: he went past Bleth: he went along the Hills of Neol-Hungar and came to the Gap of Poy. All these are in that part of the world that pertains to the fields we know; but beyond the Gap of Poy on those ordinary plains, that so closely resemble Sussex, one first meets the unlikely.
- The Long Porter's Tale, Tales of Wonder, 1916
In Dunsany, the train isn't the only way to the magical. Another route, in some of his stories, is the shop in Go-by Street, which leads through to The Lands of Dream. There's an evocative section in The Avenger of Perdondaris where the narrator, returning through the wrong portal, finds himself in a far-future London and is baffled by the language until he realises a stallholder is trying to sell him a cake:
...The door opened, and to my surprise I found myself in what seemed like a shepherd's cottage; a man who was sitting on a log of wood in a little low dark room said something to me in an alien language, I muttered something and hurried through to the street. The house was thatched in front as well as behind. There were no golden spires in front, no marvellous birds; but there was no pavement. There was a row of houses, byres and barns but no other sign of a town. Far off I saw one or two little villages. Yet there was the river; and no doubt the Thames, for it was of the width of the Thames and had the curves of it, if you can imagine the Thames in that particular spot without a city round it, without any bridges, and Embankment fallen in. I saw that there had happened to me permanently and in the light of day some such thing as happens to a man, but to a child more often, when he awakes before morning in some strange room and sees a high, grey window where the door ought to be and unfamiliar objects in wrong places and though knowing where he is yet knows not how it can be that the place should look like that.
A flock of sheep came by me presently looking the same as ever, but the man who led them had a wild, strange look. I spoke to him and he did not understand me. Then I went down to the river to see if my boat was there and at the very spot where I had left it, in the mud (for the tide was low) I saw a half-buried piece of blackened wood that might have been part of a boat, but I could not tell. I began to feel that I had missed the world. It would be a strange thing to travel from far away to see London and not to be able to find it among all the roads that lead there, but I seemed to have travelled in Time and to have missed it among the centuries. And when as I wandered over the grassy hills I came on a wattled shrine that was thatched with straw and saw a lion in it more worn with time than even the Sphinx at Gizeh and when I knew it for one of the four in Trafalgar Square then I saw that I was stranded far away in the future with many centuries of treacherous years between me and anything that I had known. And then I sat on the grass by the worn paws of the lion to think out what to do. And I decided to go back through Go-by Street and, since there was nothing left to keep me any more to the fields we know, to offer myself as a servant in the palace of Singanee, and to see again the face of Saranoora and those famous, wonderful, amethystine dawns upon the abyss where the golden dragons play. And I stayed no longer to look for remains of the ruins of London; for there is little pleasure in seeing wonderful things if there is no one at all to hear of them and to wonder. So I returned at once to Go-by Street, the little row of huts, and saw no other record that London had been except that one stone lion. I went to the right house this time. It was very much altered and more like one of those huts that one sees on Salisbury plain than a shop in the city of London, but I found it by counting the houses in the street for it was still a row of houses though pavement and city were gone. And it was still a shop. A very different shop to the one I knew, but things were for sale there shepherd's crooks, food and rude axes. And a man with long hair was there who was clad in skins. I did not speak to him for I did not know his language. He said to me something that sounded like "Everkike." It conveyed no meaning to me; but when he looked towards one of his buns, light suddenly dawned in my mind and I knew that England was even England still and that still she was not conquered, and that though they had tired of London they still held to their land; for the words that the man had said were, "Av er kike," and then I knew that that very language that was carried to distant lands by the old, triumphant Cockney was spoken still in his birthplace and that neither his politics nor his enemies had destroyed him after all these thousand years. I had always disliked the Cockney dialect and with the arrogance of the Irishman who hears from rich and poor the English of the splendour of Elizabeth; and yet when I heard those words my eyes felt sore as with impending tears it should be remembered how far away I was.
- The Avenger of Perdondaris, Tales of Three Hemispheres, 1919 (Gutenberg E-text No. 11440)
I must pass this example on to David Platt, who just contacted me with news of current updates of his Where London Stood project, which explores the meme of ruins in art and literature, particularly visions of the ruins of contemporary cities such as London.