The cost to install an operating "ABS" block signal system on the Sacramento Northern mainline to enhance the appearance and operation of the WRM museum operation would be cost prohibitive and also something very low on their priority list. I do admit, however, that it would be rather unique to have something of that order being used by museum trains.

The museum probably has enough pieces laying around to construct a couple of miles worth of signaling, for demonstration purposes. Existing rails would have to be cut to establish insulated blocks, signal poles mounted, cables buried and so forth. Are YOU coming up to help ?
Please bring your necessary tools and credentials. Sign in with Fred Krock or Dave Johnson.

We will expect your construction report in four weeks with semi-weekly updates... Sound good ?

Seriously though, many years ago when former General Manager Norm Borgwardt was alive, there had been talk of establishing at least a couple of miles of "Coded Cab Signal & Speed Control" equipment for demonstration purposes, to be utilized by the three current Key System "bridge units"... At the time, BAERA//WRM had enough gadgets laying around to duplicate a handful of blocks which really would have been a novelty for a Museum to have.
The overall priorities right now are faithful and careful "car restoration"...

There are still a number of cement bases where the OA&E (SN) block signals used to be mounted, along the current Museum trackage...

The following description of the original OA&E block signal system along this route you mention, was taken from another railfan site, and used here, with permission, for your historical review :

"The OA&E (Sacramento Northern) took special pride in its automatic block signal system that protected the mainline from Oakland to Sacramento. The Type 13A Automatic Block Signal was manufactured by Union Switch & Signal Company.

This signal installation was the only AC track-circuit system in the vicinity of San Francisco (at the time) which used light signals.

The system was operated by 60 cycle current which was supplied to the signal mains at 2200 volts at Eastport and Concord for the signals from Oakland to Mallard, and at Dozier and Lisbon for the signals from Chipps to Sacramento.

At signal locations and cut sections 0.6 kva transformers supplied current at 110 volts for relays and signals. Adjustable core transformers fed the track circuits at the center though about twenty less than 4000 feet in length were "end-fed".
All spurs had a light switch indicator to show when a train could enter the main line. Sidings had one set of home signals and were provided with light switch indicators at the East ends; sidings having two sets of home signals were provided with light switch indicators at both ends.
Signals were hung on cedar poles about 25 feet in length, with 7-inch tops, shaved and painted.

All wiring was carried down the poles and underground in redwood trunking and galvanized conduit. Bonding at switches and frogs and to connections to impedance bonds was # 0000 DBWP stranded copper.

Track circuit wiring was # 6 copper, rubber covered and all connections between the line wires and signals and relay boxes was made with # 12 and # 14 copper, rubber covered. Spare wires were drawn thru all conduits.
Distant signals (non-automatic) placed about 1000 to 2000 feet in advance repeat the indications of their respective home signals. The overlaps favored westbound trains; they varied in length from 300 to 400 feet.
There were also some 14- automatic flagman highway crossing signals, operated from the track circuits at 110 volts AC. The flagmen were manufactured by Bell & Jamison in Los Angeles...

There were 117 Home Signals and 90 Distant Signals.
There were 14 crossings operated in conjunction with the signal system.
There were approximately 300,000 signal movements per month."

Hope all this info helps.

Henry.
Oakland