I'm so pleased you like Niccolini's Song with its wonderful lullabies for trains and babies. It is, alas, out of print. Mark Buehner, the illustrator, has done a lot of other lovely books -- although none perhaps as emotionally evocative as Niccolini. He does, however, have some good dog picture books.
The Adventures of Taxi Dog, written by Debra and Sal Barracca, follows a stray dog and the taxi driver who adopts him through the streets of New York, picking up fares in rhyme. I've met a number of people who love this book a lot, but it's never resonated in that way with me. Buehner's art is good (although his version of New York is overwhelming full of white people) -- and Isabel will undoubtedly appreciate the fact that Max the dog is on every page.
Buehner did Taxi Dog in 1990, shortly after he moved to New York from Utah. Fourteen years later, he illustrated
Dex: The Heart of a Hero, written by his wife, Caralyn Buehner. It's a riot. Dex is the ultimate 98-pound weakling -- I suppose in dog terms it would be 9.8 pounds. He's a dachshund who's either ignored or ridiculed by the neighborhood dogs and cats (it looks like we're in New York still, and all characters are animals). He has Walter Mitty-esque dreams of becoming a superhero: "The Mighty Dex flew up into the dark and starry night...." So he starts training: running up and down garbage piles, dragging socks full of sand to the corner and back, doing push-ups, circling five times at night before going to sleep. My scanner is, alas, on the fritz again. I would love to show you the six-panel illustration of Dex doing body-builder poses in front of the mirror: "Faster than a rolling ball, stronger than the toughest rawhide, able to leap tall fences in a single bound!" He gets himself a superhero costume (see cover) and starts his career by helping a puppy across the street. He saves a mouse from falling down a storm drain, tackles a purse snatcher (bulldog), and organizes a neighborhood cleanup day. I love that his superhero-ness is so non-magical, and his heroic deed are so pedestrian. He takes himself very seriously.
He finally gets his wish to fly to the rescue when the cat who has been his biggest detractor gets stuck in a tree and all the animals of the neighborhood run to Dex to rescue him. Dex harnesses the laws of physics: he stands on one end of a see-saw --
The illustration is of a wide-eyed caped dachshund bouncing straight up, with caption: "The Mighty Dex flew up into the dark and starry night..." He saves the cat, the crowd chants "Su-per Dog!" and the cat and Dex end up partners in matching caped outfits."Everybody on the other end! One! Two! Three!"All the animals jumped together on the other end of the teeter-totter, catapulting Dex into the air. He soared over the crowd, his ears and cape streaming out behind him...
Buehner's illustrated some other interesting ones too: a short story by Octavio Paz rewritten for kids, and a delightful tall tale about a man who grows balloons on a farm. Stories for another night.