In 2025, the preferred alternative called for a "Pop-Up Metro" pilot service that would have utilized British Rail Class 230 battery-electric multiple units (BEMUs) repurposed from former London Underground D78 Stock.

[4][5][6] Conceptual planning for the project began in the early 2010s, with renewed focus emerging in 2024 when the Railroad Development Corporation (RDC) proposed its Pop-Up Metro concept to Johnson County officials.

[7] In January 2025, the Iowa City-North Liberty Commuter Rail project was canceled after CRANDIC refused to lease trackage for passenger service on their corridor.

Interest in reintroducing passenger rail service emerged in the early 2010s as Johnson County experienced population growth and increasing traffic congestion.

A 2012 regional transportation planning study highlighted the need for alternative transit solutions, including the potential for rail-based services along the CRANDIC corridor.

[16] The RDC proposes that Pop-Up Metro avoids the need for costly infrastructure upgrades such as full electrification; instead, it relies on trains equipped with onboard battery systems capable of recharging at strategically placed charging stations.

In August 2024, representatives from Iowa City, Coralville, North Liberty, and Johnson County traveled to Rockhill Furnace, Pennsylvania, to experience the Pop-Up Metro demonstration firsthand.

[6] On January 31, 2025, Johnson County officials received notice that CRANDIC would not allow use of the line for passenger transit, in turn indefinitely precluding all Pop-Up Metro plans.