While attending the 4rd National Garden Railway Convention (NGRC) in Denver in 1988, a group of 10 Bay Area garden railroaders, with the knowledge there were enough first class garden railways in the Bay Area, agreed to take steps to host the 5th NGRC in 1989. By November of 1988 the group had set in motion the formalization of the Bay Area Garden Railway Society (BAGRS) and invested much effort to ensure the upcoming NGRC would be a success.

One of the projects completed in time for the convention was the construction, using mostly donated material from Just Trains in Concord, of a modular railway. After the convention, this modular railway was set up for various public showings off and on for the next several years; however, several design deficiencies made operation complicated and undependable, making its productivity limited.

BAGRS hosted the NGRC again in 1993, but the condition of the modular railway had deteriorated, and there was no clear leadership of the group at the time. Therefore BAGRS hired the Del Oro modular group from Southern California to display at the convention.

Shortly after the '93 convention, several interested BAGRS members, still trying to take the modules to the public, found themselves at a civic celebration in Newark. The frustration of keeping trains running on the poorly designed modules was compounded when a bus loaded with disabled children, all in wheelchairs, arrived eager to see the wonderful trains. The module tables, built at the "standard" 44 inches off the ground, made it impossible for the wheelchair-bound children to participate in the spectacle. At that point, several members decided it was time to make a major change in the module design, not only making it more spectator friendly, but more user friendly to the club members and more topographically interesting.

Ideas were gathered from clubs around the country based on the question: "if you were to start over, what would you change?" These ideas were incorporated into a new design, mostly reflected by the design of the modules today. Several prototypes were built and tested with the old module displays and after a few shows, with beta testing complete, the new design was put into operation.

In the winter of 1993/1994, a group of enthusiasts, led by Bruce Jahn, met at Dave Gill's cabinet shop in South San Jose and over a pair of weekends, using the lumber Dave's employees had prepared combined with his inventory of shop tools, 30 naked modules were built. BAGRS President Jack Verducci gave a scenicing demo to get the group started and the 30 modules went off to homes around the Bay Area.

The new modules were debuted at the BAGRS annual meeting in Milpitas in the spring of 1994 and were received so warmly the group almost doubled in size and immediately there was a need to build more modules. Enthusiasm grew over the years so that at the 22nd NGRC in 2006, the BAGRS Shortline was set up in a "U" shape encompassing a length of 156 feet and a width of 40 feet. By this time, the "new" BAGRS Shortline had set up and displayed over 150 times at venues spread throughout Northern California.

By the winter of 2007/2008, it was time for a major change in the BAGRS operational direction, as membership was dwindling and there was a feeling the "good ol' boy's club" of old was gone. With new governance voted into office in the spring of 2008, many new directions were taking course. Budget considerations were paramount in attempts to get the club back on track and some changes not always popular with the remaining membership occurred. Hard decisions had to be made, including elimination of paper newsletter publishing and the removal of the modular group from the overall BAGRS plan.

The new BAGRS governance, faced with their decision to eliminate the module group but aware of a hefty inventory of assets directly tied to the modular group, proffered a proposal to the small special interest group of module owners. The small group was given the opportunity to continue operation of the portable layout and ownership of all BAGRS-owned inventory, including a newly purchased pick-up truck and trailer, would be transferred to a new, independent, group. This would be accompanied by a one-time financial gift to help jumpstart the group's administrative and insurance requirements. The caveat to the offer was a lien on the equipment for four years to ensure it would be protected in a professional manner, that the group would be successful, and that the group would continue to promote garden railroading and BAGRS. After the expiration of this four-year period the equipment would become property of the new group. It was also requested by BAGRS that the new group seek non-profit status with the United States Internal Revenue Service.

A meeting was called with interested module group members to form a plan. Questions were raised about the feasibility of the new organization, management, formalization, and members' volunteer requirements. Over the next several weeks, with much membership input, a name was developed and the first five-member board selected. The new board then secured a mailing address, prepared and filed necessary paperwork with the State of California (including articles of incorporation and bylaws), prepared and filed an application with the IRS for non-profit 501(c)(3) status, obtained insurance, and established a banking relationship.

On September 30, 2008, legal papers were signed and the agreement put in place severing the new organization, named the Diablo Pacific Short Line (DPSL), from BAGRS. The DPSL was then off and running. In short order the branded color of fire engine red was selected, a new logo was finalized, and the first 31 charter member households officially joined the group. In addition to new member fees and the one-time gift from BAGRS, both DPSL and BAGRS members provided substantial monetary gifts to help the group get firmly grounded. In April 2009 the DPSL officially received 501(c)(3) status from the IRS.

On October 27, 2012, the four-year lien period expired and the BAGRS governance released the lien on the Diablo Pacific Short Line (DPSL) equipment. The DPSL is now a separate and independent organization.

Ever since its incorporation membership in the DPSL has steadily grown. There is now an unprecedented level of interest and enthusiasm among the membership and the group has worked diligently to improve train operations and the physical appearance of the modules. A new name and presence has been established for the group, with a growing number of new exhibit venues. While the DPSL continues to exhibit at many traditional venues associated with the group during its BAGRS days, every year brings two or more additional new exhibit opportunities, helping to expand the group's range and exposure. It is great fun to be part of the DPSL, where every member is valued and appreciated.