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California \ Monolith Portland Cement Co.
Reference Data.
Corporate Ownership.
Los Angeles Municipal Cement Mill
1906 - 1921
U.S. Potash
July 1921 - February 1922
Monolith Portland Cement Co.
February 1922 - 1986
Calaveras Cement Co.
1986 to 1995
Lehigh Cement
1995 -
Lehigh Southwest Cement

Rail Weight.
35 lb initially
60 lb at end of operations

Track Length.
At end of operations:
Mainline – 3 miles
Quarry – 1 mile

Last Updated: August 25, 2015

Monolith Portland Cement Co.

By Randy Hees.

I n 1921 the Los Angeles Municipal Cement Mill was no longer needed for the L.A. Aqueduct project and sold to the U.S. Potash Company. After a short year of ownership, the property was transferred to the newly organized Monolith Portland Cement Company.1 Following the change in ownership, a series of improvements were made to the mill and railroad.

Within 6 months the newly formed company purchased the first internal combustion locomotive for the railroad, a 7 ton, friction drive Plymouth BL. It was followed within a year by a second Plymouth, this time a 7 ton mechanical drive DL. It is believed that both of these locomotives were used exclusively in the quarries, or to dump waste dirt from the crusher. The addition of locomotive No 7, a 30 ton Plymouth model WL for use on the mainline in 1929 lead to the retirement of the steam locomotives. Originally the quarry and main line were connected, but eventually that steep connecting line was removed, and a separate repair shop was established for the quarry equipment.

In 1936, a quarry operation was substantially changed, when an underground operation serving the “Jameson” quarry was added. This included a 200 yard long tunnel to the underground quarry, with two electric locomotives used. It is reported that the original plans called for the electric line to loop around and serve the crusher directly this was never built. Instead one of the “quarry” Plymouths would haul the quarry cars from the mouth of the tunnel to the crusher.

Over the years, the operation converted from bottom dump cars to rotary dump cars. The last significant upgrade to the railroad was the purchase of 28 new 7-ton rock cars built by Easton Car Company for the quarry division. These cars had roller bearings and conventional knuckle couplers. The main line continued to use the older 10 ton cars with link and pin drawheads through the end of railroad operations.

The electrified quarry operation was shut down in July 1972, and was replaced by trucks. Plymouth No 14 continued in service in the quarry to move waste dirt from the crusher. The mainline would operate into 1973, as a new conveyer system was built paralleling the railroad. Regular railroad operations ended on January 13th 1973. There was one final run, a special train for the local high school’s journalism class in early February.

The end of railroad operations occurred as the “company” town of Monolith was shut down and abandoned along with the general store, the post office and the SP depot. Most of the population moved to the nearby town of Tehachapi.

In 1975, after the close of railroad operations, some of the railroad equipment was sold to Magic Mountain to be repurposed as the “Grand Centennial Railroad Excursion” ride. That ride was removed in 1985.

The plant continues to operate today, albeit much modernized as the Lehigh Southwest Cement Company. It has been immortalized in song by John Fahey, in his 1964 song, The Portland Cement Factory at Monolith, California.

Revised: August 29, 2015
1. Building and Engineering News, Feb 25, 1922.

Gary G Allen, "Narrow Gauge in the Tehachapis", Pacific News, November, 1974, No 157
February 1973 RAILROAD MODELER magazine

Reference Material Available Online:

Equipment Rosters.

Los Angeles Municipal Cement Mill / Monolith Portland Cement Roster by Randy Hees.


The Route of the Monolith Portland Cement Co. circa 1966 for Google Earth by Andrew Brandon.


Collected Monolith Portland Cement Company Photographs.
Images collected from private collections, libraries and historical societies.

Photographs of Monolith from Lee Williams at Williams' Cyber Niche. (

California \ Monolith Portland Cement Co.
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