Services between Ipswich and Cambridge and Ipswich and Peterborough are currently not running due to a lorry becoming stuck under a bridge.
Network Rail engineers are assisting with freeing the lorry, whose container has come wedged under the bridge on Saxham Road.
An inspection will need to take place once the vehicle is freed to ensure the line can be safely reopened.
Passengers are being advised to check how their journey is affected.
According to Network Rail, bridge strikes are an expensive problem for the railway and can cause delays to both train services and the road network while damage is assessed.
Bridge strikes cost the UK taxpayer millions every year (Network Rail).
The route director for the Anglia branch of Network Rail, Ellie Burrows, said: "There is no excuse to not know the height of your vehicle before starting your journey.
"As well as putting lives in danger on both road and rail and causing lengthy delays for passengers and road users, drivers who chance it at bridges are at risk of losing their licenses and leaving their employers with a hefty bill for repairs and train delay costs, along with a strong threat to their own operators licence."
The main culprits for bridge strikes are HGVs and buses across the UK, at a cost of around £13,000 per incident, totalling to around £23 million each year for the taxpayer.