I was "Googling" around and found some articles from June-September 1910 from Railway and Locomotive Engineering. I thought some of you might like the images. The official opening for Penn Station was August 1, 1910, right around when this series of articles came out.
"Back in the day," The New York Times summed up the (then high) technology and results as "Pennsy's North River Tunnel a Marvel of Skill."
Included is a picture of the tunnel portals as well as a map of the tunnels from Bergen Hill, NJ to under the Hudson and East Rivers. The fact that these tunnels linger on is a testament to the Pennsy and its engineering. Any of us that live in the NY Metropolitan Region know that these aging tunnels have been getting plenty of attention lately.
The Pennsylvania Railroad Technical & Historical Society ran a timely article in its Winter 2014 edition of The Keystone, which mentioned that the condition of the tunnels, now 105 years old, were made worse by the impact of Hurricane Sandy. The article by George Pins came out coincidentally several months before a rash of train delays related to the tunnels.
In spite of several problems this year with Amtrak trains and New Jersey Transit, it is pretty amazing that the tunnels built so long ago continue to serve the region.
Tom
(Note-If this turns into a political discussion the topic could be deleted, so proceed with caution)