Antipolo extension.-(40 kilometers.) The first section of this line was opened to public traffic from the Manila station to Pasig, 16 kilometers, on December 22, 1905. The second section, from Pasig to Rosario Junction and thence to Taytay, at 25 kilometers, was opened February 22, 1906, and the third section, from Rosario Junction up the left bank of the Mariquina River to Mariquina, a distance of 4.5 kilometers, was opened March 17, 1906. On this line there are 5 steel bridges, 5 pile bridges, and 39 cement and masonry culverts. The San Juan River is crossed by a steel bridge of four 66-foot spans in concrete cylinder foundations, and the Mariquina River is crossed by a similarly constructed bridge but consisting of five 100-foot spans. A ferry has been constructed between Fort McKinley station and the military wharf on the other side of the Pasig for the transportation of quartermaster wagons and military supplies. A request has been made for the construction of a rack railroad of the " strub system," not to exceed 2 kilometers in total length, on the last section of 7 kilometers to Antipolo. This type of construction was deemed the best method of securing ascent of the difficult hills in the climb to Antipolo. This matter is still pending. On May 15, the company was granted an extension of time from May 23, 1906,until December 31, 1906, for the completion of the whole line. The number of passengers carried on this line during the first half of 1906 was 258,612, or more than a third of the number carried upon the main line for the same period. The line is to be double tracked up to the Santa Mesa station and a spur line of 3 kilometers will be constructed to and across the Pasig River for connection with the proposed lines through the southern provinces.
Title: Annual report of the Directory of Lands. 
Author: Philippines. Bureau of Lands.
The three cylinder piers of the San Juan River Bridge are the only remaining structure left. The bridge construction is similar to the Quingua Bridge in Pampanga. The building at the back of the three piers is the Market Place located at Kalentong St. Mandaluyong City. The market outgrew the railroad line that is responsible for its existence.
The construction of the new market led to the demolition of the beautiful Kalentong overpass at Daang Bakal. Daang Bakal is the term used by informal settlers for railroad. There is also a Daang Bakal in Marikina and near the end of the line in Montalban.
At the Boni St. crossing, the railroad tracks are now covered with asphalt. Yellow lines mark the spot, a unique pedestrian lane in the middle of the road intersection. Most of the residents of Barangay San Jose reside along this line. Same as with Daang Bakal, Hulo and Barangka Ilaya. These four barangays are the most densely populated area of Mandaluyong City.
Except for the houses and narrow street that mark the line, practically all the railroad structures in Hulo including the San Pedro station are now gone. The Rockwell Plant opposite Hulo is now a mall, there is a new Hulo-Makati bridge and a new ferry station was recently inaugurated but commuters still cross the river (to Makati) using the banca similar to what railroad commuters did when the line was still operational.
To be continued...