Postcard showing the Callahan Line Change area before construction between 1921 and 1925.
Callahan Line Change shortly after completion in 1926, looking northerly. Courtesy – Caltrans
Just above Castaic, still a part of the Castaic Grade, the Ridge Route was realigned to remove a few big curves. In March 1925, a particular realignment known as the Callahan Line Change, was graded to reduce seven sharp curves down to two gentle curves. By July 1926, the new alignment was paved and in use.
Looking toward the Callahan Line Change location in 2020. Original pavement can be seen on the bench about 2/3 up the slope across the freeway.
Callahan Line Change area in 2018. Third curve (second on left) visible in the 1926 photograph, can be seen at Location A in the 2018 photograph.
Closer view of the remaining concrete and curbing, adjacent to Location B. Courtesy – Caltrans.
USGS topographical map showing the area. The “Line Change” is adjacent to the road marked “Route” at the center of the map. Purple line indicates southbound I-5.
In 1970, construction of the southbound lanes of I-5 caused the old Ridge Route to be realigned once more. The Callahan Line Change happened to be in the way of the new lanes. Today, where the Line Change was is no more with little exception. The old Ridge Route runs parallel to the southbound lanes along this section. A small ledge, across from the “new” Ridge Route is all that remains of the Callahan Line Change. Some curbing, as well as concrete paving, still remains visible today.
Looking southerly at the upper section of the “Callahan Line Change” segment of the Ridge Route. This was bypassed in 1969 when the southbound lanes of I-5 were constructed.
Looking up Marple Canyon from the Ridge Route. Concrete in the foreground dates to 1919 and was bypassed in 1969.
Looking northerly on the 1925 paving. Southbound I-5 is to the right with the relocated Ridge Route to the right of that.
Looking southerly along the 1925 paving. The original alignment follows the bend to the right. Southbound I-5 is to the left.
Section of original curbing visible adjacent to the large rock on the left. This was bypassed in 1925.
At the north end of the 1969/70 reconstructed section of the Ridge Route, some concrete and paving are still visible. North of this point, the Ridge Route returns to its original alignment.
