I know of only two monuments which are dedicated to the building of the railway - one in Indonesia, and one in England. I have read however, that there used to be another, also in Pekanbaru, at the site of the main cemetary; but this was removed during Sukarno's regime at the request of the Japanese.
The monument which is now in Pekanbaru is a locomotive which was used on the railway. This has been placed on a concrete pad, which itself has murals on two of the walls. One, shows a map of the railway, and the location of the camps on it, and the other has pictures of those building the railway, and their guards. Over the last 10 years this monument has gone from disrepair to being looked after, and once again has fallen into disrepair, with the concrete pad cracking badly. There is also a stone here which has a dedication to those who built the railway. The area surrounding the monument here is a cemetary, for all those romusha who survived the war and stayed in Sumatra.
The monument in England is located at the National Memorial Arboretum in Staffordshire, and was first dedicated on the 15th August 2001. I have taken these photos from another site .
There are also the remains of a locomotive at Lipat Kian, which is just a rusted shell, and is located in a Cacao plantation.
There are more pictures of these monuments in the photo gallery.
If you know of any other monuments please let me know so I can add them.