Information for the above article compiled from data information supplied by Jack E. Schramm, courtesy of "DSR BUS ROUTES, 1922-
("Detroit's DSR, Part 1" — January–February 1991 edition of Motor Coach Age magazine), "DSR BUS ROUTES, 1932-1945"
"Detroit's DSR, Part 2" — March–April 1992 edition of MCA magazine),  and "DSR BUS ROUTES, 1945-1974" ("Detroit's DSR, Part 3"
May–June 1993 edition of MCA magazine).  Additional  info obtained from 1950-54 DSR Headway Reports courtesy of Tom Breeding,
and from 1951 thru 2005 DSR and DDOT Service Maps and timetables already in the author's possession.  Holbrook route-map, timetable
and transfer images courtesy of the Stan Sycko collection.  Information on the various Detroit area auto and military facilities obtained
through various online sources.
© 2010
During 1940 and 1941, the DSR began making significant improvements to its bus operation by
extending some lines and adding new routes. As a result, ten years after it was discontinued, service
on the
Holbrook route was restored by the DSR, effective Monday, October 6, 1941. This new
bus line would travel considerably farther than the short feeder line which operated a
decade earlier. Although this new service would also begin at King and Woodward, and travel via

, the route would now also operate via Buffalo, Charles, Mt. Elliott, and Eight Mile to Mound
Road, providing auto workers with bus service to
Chevrolet Gear and Axle (today, American Axle
and Manufacturing (AAM))
, Briggs Manufacturing (later, Chrysler Outer Drive Stamping, now
Chrysler's Mt. Elliott Tool and Die), and
Chrysler's Warren Truck Assembly Plant. But the United
States' involvement with
World War II would soon extend the line well into the northern suburb of
Warren Township
(later incorporated as the City of Warren in 1957), where the line would continue to
provide bus service for the next 56 years.

Many months before this country's entry into World War II on December 8, 1941, the
t had completed construction at two government-owned contractor-operated facilities in
Warren Township, which were initially built to supply arms to the Allied war effort. The first of the two
facilities to be serviced by the
DSR was the 15-building Hudson Naval Ordnance Plant — built in
1941 at Mound and Nine Mile Roads by the
U.S. Navy for the Hudson Motor Car Company to
manufacture various types of artillery and shells. Beginning March 2, 1942, the
Holbrook Extension
bus route was launched to shuttle workers the extra mile or so along Mound Road, from Eight Mile to
Nine Mile Roads, to the new
Hudson Naval Ordnance Plant.(This same facility was subsequently
managed by Westinghouse and Ford Motor Co., before it would later become Chevrolet Division,
Warren, but known today as the GM Powertrain Division plant.)

The other government-owned facility was built in late 1940–'41 on 113-acres of farmland, also in
Warren Township, and was known as the
Chrysler Detroit Arsenal Tank Plant. This mammoth, 105-
building, complex was located within an area bounded by Van Dyke, Twelve Mile, Mound and Eleven
Mile Roads. The facility was built by the
Chrysler Corp and the U.S. Army for the mass production of
M3 and M4 Sherman tanks. The tank plant alone measured five city blocks deep and two blocks
wide and was designed by industrial architect Albert Kahn. During World War II the facility built one
quarter of the tanks produced in the U.S. Bus service to the
Detroit Tank Arsenal began on April 13,
1942, when the
Holbrook Extension shuttle was extended two miles further up Mound Road and
routed via Eleven Mile and Van Dyke to the tank plant's main entrance on Van Dyke, near Martin

With the
U.S. having now "officially" entered into the war, and "war-time" production already in high-
gear at auto plants across the Detroit area, the bus service on the
Holbrook route was also being
geared up for the war effort. Effective on September 1, 1942, the
Holbrook Extension shuttle route
was discontinued after the
Holbrook route was extended north along Mound Road, providing service
directly to the
Chrysler Tank Plant. Beginning on March 30, 1943, the line was rerouted via Twelve
Mile Road (instead of Eleven Mile) to south on Van Dyke, to the tank plant's main entrance. The war–
time headways on the
Holbrook line averaged one to two minutes during the peaks hours  and 12
minutes during the base and evening hours. The owl service to Eight Mile and Mound operated under
30-minute headways.

During the war, the city of Detroit was acknowledged by
President Franklin D. Roosevelt  as "the
great arsenal of democracy"
because of the rapid conversion of much of the area's automotive
industry to produce armaments during the war effort. It should also be noted here that the
of Democracy"
nickname could not have been adopted by the city if it were not for the assistance
given by the
DSR in providing transit services to the area's automobile plants during World War II.

By the 1950's, the majority of the service on the Holbrook line now terminated on Mound Road, just
north of Nine Mile Road, at the Naval Ordnance plant (now the
Ford Naval Arsenal), although shift-
change trips would continue to travel via Mound and Twelve Mile Roads to the
Chrysler Tank Plant
on Van Dyke. According to a September 6, 1950
DSR Weekday Schedule Analysis Report, 18 to 21
of the 31-passenger
Transit Buses were required to operate during peak hours, while five coaches
were required for base operation. Now assigned out of the
Woodward Terminal in Highland Park, a
total of
31 runs were required for daily operation weekdays, including 4 straight–day runs, 7 straight-
night runs,
14 swing-day runs and 6 swing–night runs, operating under 1–2 minute headways during
peak hours and a 15-minute headway during the base operation. Although two coaches provided owl
service to Eight Mile in 1950, 24–hour service was discontinued shortly afterwards.

By the late–1960's, 24-hour operation had long ceased and Sunday service had also been
discontinued. Headways had increased to 8–-10 minutes during peak hours and 30 minutes during
base and evening hours. However, although the base of the service still terminated at 9-½ Mile Road,
at the
Chevrolet Division, Warren plant (former Naval Ordnance plant), effective February 7, 1966,
much of the service between 6AM and 9PM was extended even further along Mound Road, past the

General Motors Tech Center
, to Chicago Road—just north of 13 Mile Road (see map above).
Certain peak-hour trips also operated to the
Detroit Tank Arsenal plant and only a few to the U.S.
Army Tank-Automotive Center (ATAC)
, located adjacent to the tank arsenal, on Eleven Mile Road
east of Mound. But effective on September 9, 1970, all
Holbrook service north of Eleven Mile Road
was discontinued, as the
DSR began scaling back its suburban operation, and the route was cut back
to Eleven Mile and Mound, thus ending service to the tank plant on Van Dyke.

By 1973, all
Holbrook service would terminate on Mound Road at 9-½ Mile, with the exception of a
few peak-hour trips operating to Eleven Mile and Mound, to the
U.S. Army Tank-Automotive
Command (TACOM)
. By this time, service had dwindled to 14–15 minute headways during peak
hours and 35 minutes the rest of the day. After the closing of the
Highland Park Terminal in
December of 1970, the operation of the line had been transferred to the
Gilbert Terminal, but was
later reassigned under
DDOT to the east-side Shoemaker Terminal during the summer of 1979.

Over the next few decades, the service on the
Holbrook line would continue to decline. In 1989, the
weekday service was cut-back to peak-hour only operation, terminating after 7PM, and Saturday
service was also discontinued (although the Saturday and mid-day weekday service were restored in
June 1997). By the early 1990s, headways were averaging 25–35 minutes. In late 1997,
Dennis W. Archer
announced that the city could no longer afford to operate its buses outside the
city limits. Consequently, effective on Saturday, January 17, 1998, all
Holbrook service along Mound
Road was discontinued and the route was terminated at Eight Mile Road (the city limits), thus ending
56 years of service through the northern suburb of Warren.

By the arrival of the 21st century, things would only get worse, as ridership numbers continued to
plummet and the line was threaten with possible elimination of service. Effective April 23, 2005,
Saturday service was once again discontinued and the weekday service now increased to 60-minute
headways. As a result, the
Holbrook line, which at one time served as a major auto–worker route and
required over twenty coaches to maintain service, had now been reduced to just one coach to provide
the required service.

After years of threaten elimination due to low ridership, the
#24 Holbrook line was discontinued by
after nearly sixty-eight years of continuous service. Effective Saturday, September 26, 2009,
service on the line was cancelled.
Although the former D-DOT Route #24 Holbrook
never achieved the familiarity  that a number of the
city's more prominent bus routes would attain, this
rather little known bus line—along with other DSR
routes—played a contributing role in helping Detroit
acquire the status as "The Arsenal of Democracy"
during WW-II. Not only did the Holbrook line provide
the needed bus service to transport workers to the
numerous auto plants located along its route—which
were converted to the production of war materials
during the war—but would continue providing its
service to auto workers during most of its nearly
sixty-eight years of operation.

Initially, the history of the Holbrook bus line goes back to
the early years of the
DSR's Motor Coach Division,
which began operations in January of 1925. In those days,
DSR bus routes were just short feeder lines used to
service the major streetcar routes, and provided a less
expensive mode of transportation to newly developing
districts of the city. The first
Holbrook bus service began
on Tuesday, September 6, 1927, and only operated
between Woodward Avenue in Detroit and Jos Campau in
Hamtramck. However, because of equipment shortage
problems, the line was discontinued after only seven days.  
But after improving the scheduling on other lines the
was able to resume the service on October 24, 1927, and
the route was extended east to Conant, resulting in a two-
mile feeder line, which was initially assigned to the
Avenue Garage
in Highland Park.  However, after three
years of operation, the line would fall victim to the Great
Depression and was canceled on February 9, 1931.
D.S.R. Route #43
D-DOT Route #24
This 1966 DSR map displays the route followed by
the Holbrook bus line when the route operated 5½
miles outside the Detroit city limits, to Chicago Rd.
The above map shows the route of the #24 Holbrook line during its last years of operation. In addition to
servicing numerous auto, manufacturing and supplier plants along its route, two nearby high schools,
Detroit's Northern High and Hamtramck High in Hamtramck, were also serviced by the Holbrook line during
most of its nearly sixty-eight years of operation.