Boardman’s testimony about AMTRAK dealings with hurricane “Sandy” mentioned high density signaling. here is a quote from his testimony ------
""One lesson we’ve learned is that high density signaling in the East River Tunnels between New York and Queens would be a simple and comparatively inexpensive improvement that would greatly improve our operational flexibility. We have high density signaling in the two North River Tunnels between New York and New Jersey to accommodate the traffic, but it hasn’t been installed in the East River Tunnels because there are four of them. Because the damage in the two flooded East River tunnels was more extensive, we have not yet been able to return them to full service, and that meant that the undamaged pair of tunnels has had to carry a heavier traffic load. We can do it, but high density signaling would allow us to carry a much heavier traffic load on the same infrastructure, and would provide a much greater degree of flexibility and resilience. “”
What eactly are the differences between high density signaling and regular signaling ?
Is signal spacing different ?
are there more signal aspects that control speed more ?
how is cab signaling effected ?
What are the differences in headways ?
Is it predective ?
do the north river tunnels use ACSES ?
Any other characteristics ?
If installed in east river tunnels would that enabl LIRR to run full schedules while the track panels are replaced in the tunnels ?
Interesting question(s). I first think that terminology, etc., is changing so quickly we cannot keep up with it. But high density signaling would probably mean short blocks and overlapping blocks to keep trains moving rather than stopping them out in a long line. In effect, trains could be operating on the markers of the trains ahead but not necessarily at great or greater speeds. I don’t believe it exists in the North River tunnels. East River tunnels have the full schedule of LIRR and Amtrak New England trains plus LIRR and Amtrak and NJT moves in and out of Sunnyside Yards…so there is a lot of traffic in those four bores…
The High Density Interlocking (HDIS) system is in service between A Interlocking, in New York, and REA interlocking, in Harrison NJ, including the North River tunnels. Although this is Amtrak’s ROW, it was largely paid for by NJT as part of the Secaucus Transfer and Kearney Connection projects.
Note that “high-density signalling” doesn’t mean lots of signals alongside the track. As I recall there are no visible signals in the North River tubes now.
If you stand on the platform at Secaucus and watch the eastward signal after an eastward train passes it, it might go from stop-and-proceed to a couple more aspects before the train ahead passes the next signal. I think it can show approach-limited before the train ahead passes the next visible signal, about 0.7 mile east of the signal at Secaucus.
“Facing a rise in commuter trains into New York’s Pennsylvania Station, Amtrak and its commuter railroad tenants are installing a new High Density Interlocking System (HDIS) to better regulate train flow along the doubletrack “high-line” between Newark and Manhattan. Adjustments in cab signals and automatic track signals are expected to increase peak capacity from 17 to 25 trains an hour, while cutting headway from 3 to 2 1/2 minutes. Work inside the station is underway to smooth passengers’ exits from platforms and take advantage of the new companion terminal in the 1913 James A. Farley Post Office Building, scheduled to open to passengers in 2005.”
These links certainly answer some of my questions.
appears signal spacing is not closer although it certainly could be.
headways definetely closer.
appears predective
if HDIS is installed the east river tunnels certainly could have one at a time closed for long periods of time for maintenance ie regular 18 times 4 = 72 per hour 30 times 3 tracks = 90 trains. that would certainly allow maintenance on one east river tunnel to go on continously.
knowing that HDIS is installed from “A” to near Newark Penn helps us understand the traffic.
I wonder if the proposal of MNRR to run some service from Rochell - NYP would require HDIS over the Hell Gate route? also the possibility of a third track with HDIS would help for the proposed stops into NYP.
How much more intricate would HDIS on a single track be than on double track? Is the operation through the North River tunnels double track or two track?
I thought, when I read the two articles on signaling in Trains about sixty years ago, that I knew about signaling. I have learned much more since, and this is really fascinating.
Thanks; you answered my question even though I had it badly phrased. So, each track is set up for the high density operation in both directions. I had the impression that this is so so that both tunnels could be used in the same direction at the times when many trains would be going in the same direction, but I was not sure.