Pertaining to all railroading subjects, past and present, in New Jersey
- Posts: 3057
- Joined: Sun Mar 14, 2004 7:44 pm
- Location: Southeastern PA & Cape May County, NJ
Be very careful with Google's imagery. It is not real time and regardless of the copyright date may be several years old. Any given area may be stitched together from various dates. I just checked the overhead of my daughter's house in Bucks County and despite a 2014 date the picture it shows a pickup truck (my granddaughter's) which has been on the west coast since 2010!
You are absolutely correct and I have noted the same on several occasions.
The picture I viewed was on Street View from the N. Commerce Street grade crossing and is dated October 2013. It was definitely taken after the derailment as the A frame for the bridge is also gone and the base for the now removed signal can be seen when zooming in. The satellite image is much older as it still shows the bridge in the open position and the A frame still standing despite the 2014 Copyright date.
- Posts: 118
- Joined: Mon Aug 15, 2005 11:28 am
Jersey_Mike wrote:I hope the new bridge will also be an A-Frame. Does anyone know of any such bridges in existence?
JM, A-frame technology has been obsolete for many, many years....that's probably one of the underlying causes of the failure- CR kept the bridge in service long beyond when it *probably* should have been replaced. They automated the controls to eliminate the Bridge Tender position. They used to employ a person to operate this and 1-2 other movable bridges in S. Jersey.
Since this is such a short span, I believe the A-frame design was the most economical movable bridge design for that location when constructed- the creek channel was too narrow for a center-pivot swing span, and a bascule-type draw or vertical lift would've been too expensive at that time. The A-frame bridge swung open kinda like a door, and the frame was held in tension both to the fixed bridge span and the swinging girder with a large diameter rods (with turnbuckles to adjust for cyclical thermal movement) near the far end of the bridge.
There's a Youtube video referenced earlier in this thread that shows the operator opening and closing the span back in 2000. One of the locking mechanisms was located under the track structure- the operator inserts a long pipe with something like a 'key' on the end which engaged the north side mechanism that locked the bridge to shore. He made about 2 complete circles to finish the locking procedure. There were also topside locks at the south end. Don't know how that was modified when the bridge was modernized, but the video is worth a look.