Spark Core Access Tunnels
- The Spark Core Access Tunnels are a collection of passageways on Cybertron from the Cybertron portion of the Unicron Trilogy continuity family.

The Spark Core Access Tunnels are constructions on Cybertron located at least under the capital city of Iacon. It is unknown what there purpose is but to provide relatively easy access to the heart of the planet, which anyone wishing to harm Primus must think is a sweet design feature.
Fiction
Cybertron comic
Downshift was located in Spark Core Access Shaft 19A when he had to prevent Ramjet, his Mini-Cons, Nemesis Prime and some Scrapmetals from reaching Primus. Even with the automated defenses on his side, that was one fight with a predictable outcome, so he sent out an emergency call to any Autobots that had not yet evacuated. Vector Prime, Safeguard and Sentinel Maximus picked it up just as they were about to leave the Kalis Primary Energon Reserves Control, so Vector Prime used his space-warping powers to get them to the crime scene in an instant. Balancing Act, Part 4 Ramjet ordered Nemesis Prime to continue to Cybertron's core while he would take care of the reinforcements. Vector Prime in turn ordered Sentinel Maximus to stop Nemesis Prime while he would take care of Ramjet. As Ramjet and Vector Prime burst through Shaft 19A's roof to continue their battle above rather than below Iacon, Skyfall helped Downshift down from the wall he had been pinned onto, while Sentinel Maximus followed and battled Nemesis Prime all the way to the heart of Cybertron. Nemesis Prime locked his opponent outside of the core chamber and prepared the Dead Matrix to destroy Primus. Balancing Act, Pt 5 He was stopped by Omega Prime. Revelations Part 1