Published Tuesday, 10 August 2010
The 53-year-old was detained in the city on Monday evening.
A 42-year-old man arrested on Saturday is still being questioned by police.
The 200lb bomb exploded outside the station during the early hours of last Tuesday morning.
Extensive damage was caused when the proxy device, which was planted in the boot of a taxi which had been hijacked at gunpoint, exploded and ripped through a number of nearby shops.
A dissident republican organisation calling itself Óglaigh na hÉireann said it was behind the attack.