It occurred to me that Ipswich station doesn't appear to have a SideTracked cache, so something had to be done about that.
Ipswich station was opened in 1860 and lies on the Great Eastern main line with branch lines to Felixstowe and Lowestoft. To the south, the line enters the Stoke Tunnel where prehistoric remains, including woolly mammoth were found when the tunnel was excavated. Until recently, all railfreight from Felixstowe came into the station area. The recent construction of the "bacon loop" across the site of an old meat factory means that freight destined north no longer needs to be shunted and can travel directly.
From the cache, you have a view of the platforms and the tracks crossing the railway bridge.
Please note that the cache is not on railway land and you do not need to enter the park in order to retrieve the cache.
You are looking for a magnetic nano.