Rahmi M. Koç Museum

The estuary that is the Golden Horn is often overlooked when touring Istanbul, though these days it has increasingly more to offer. If you choose to visit the Eyüp mosque complex and Pierre Lotti cafe at the top of the waterway by boat, on your way up the Golden Horn about halfway on the right (or more correctly on the eastern shore) you will pass a submarine at water level with a red London bus dominating the shoreline. This is Istanbul's only museum of transport, the Rahmi M. Koç Museum, stuffed full of Koç's personal collection housed in an old Ottoman navy anchor foundry and also occupying the site of an historic dockyard. With every possible type of transport mode covered there are also reconstructions of craftsmens' workshops and nostalgic apothecary and toy shops. Highlights for me include the steam engine (constructed in West Hartlepool) salvaged from a long-since scrapped ship, which on the press of a button slowly pumps into action again. It was interesting to see two examples of the Turkish Anadol model of car from the 1970s on display as well as a large array of phaetons and a first-world-war British Albion x-ray ambulance which ministered to injured troops on site. The Sultan's sumptuous 19th-century train carriage takes pride of place in the section on trains and trams, where there is even the workings of a funicular railway (visible in the foreground of the photo above). These few examples give an idea of the impressive array of exhibits. Extras include a tour of a second-world-war American submarine, a short tour of the Golden Horn on a steam tugboat and a ride on a diesel locomotive. The museum is good value at 10TL (about £4) and the extras are 5TL (£2) a time; you can easily send half a day there given the range of items to tour.
What it is: Rahmi M. Koç Museum, a great collection of small and large modes of transport, extras include a display showing how olives are pressed mechanically to make olive oil
Where it is: Hasköy Caddesi, no.5. I jumped on a dolmus from Sishane, the journey taking just 10 minutes or so. There are also buses from Eminonu (47) and Taksim (54HT). The boat which runs from Üsküdar to Eyüp stops at Hasköy. As always in Turkey it's best to check with the driver in case routes have changed, they're always happy to assist!