The Lathrop Wye is why Manteca-Lathrop will be the undisputed center of Northern California passenger rail travel in the coming years.

The wye is railroad lingo where three rail lines meet in a triangle.

In this case, it is the Union Pacific Railroad’s Fresno main line that runs through the heart of Manteca and the Altamont Pass line that originates in Lathrop, forms the common boundary of the two cities, and runs to San Jose.

It is that wye, that starts just northwest of the Manteca Unified School District office complex, is where ACE trains from downtown Manteca starting in 2026 will switch to the Altamont line for the journey to San Jose.

The San Joaquin Regional Rail Commission is now soliciting bids to construct a concrete box culvert for the Lathrop Wye that will accommodate upgrades including double tracking all the way to just beyond the Manteca Transit station.

Work is targeted to begin in the coming months.

It is the first phase of an overall $30 million project that will take 23 months to complete.

Besides Lathrop Wye upgrades and double tracking through Manteca, it will include the construction of a North Lathrop Transit Station at Sharpe Depot off of Lathrop Road.

The transfer station in north Lathrop includes a parking lot, a drop-off zone,  a long-covered pedestrian bridge to reach a center loading platform, bus transfer center, bicycle and pedestrian access and an access road for West Lathrop Road.

The parking lot could ultimately be expanded to handle 3,500 stalls. That would make it the largest parking lot in the South County with a  capacity rivaling large regional malls. There are 1,992 parking spaces at Orchard Valley in Manteca.

The transfer station will be roughly a mile from Manteca’s Airport Way and Lathrop Road intersection.

Both the Lathrop Wy and the transfer station will play a key role when high speed rail’s initial trains start running.

The high speed rail passengers will transfer to ACE trains in Merced and then travel to San Jose, San Francisco, or Sacramento after passing through the Lathrop Wye.

In addition, the transfer station is designed to accommodate the Valley Link service to the Dublin/Pleasanton BART station that is moving toward its first phase of operation later this decade.

A separate project will add a center loaded platform and pedestrian crossing adjacent to the existing Manteca Transit Center along Moffat Boulevard.

This would allow for boarding when double tracking is in place.

Additional parking will be added almost to Garfield Avenue.

The Manteca work would cost $25 million — part of the cost deals with working around a PG&E pipeline — and take 22 months to construct.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com