DC to AC at Woodlawn

The New Haven motive power’s ability to switch from DC third rail (600 Volts) to AC catenary wire (11,000 Volts) and visa versa seems to have been a uniquely New Haven concept. How did the locomotive engineer switch from DC third rail to AC catenary wire? Did he coast the train into a dead zone at Woodlawn and then raise the pantographs once under wire?

If there was an overlap of electrical systems, what prevented an accidental dual application of both the third rail pickups and the pantographs? How did a motorman of a long MU train know all the pantographs were under wire before raising them?

The Metro North has now extended third rail to Pelham. What is the thinking on this one…cheaper to maintain than the previous overhead wires?

At Woodlawn as well as at the new location for Metro-North in Mount Vernon the third rail ends at the point where the wire begins. The enginer just coasts through the changeover area and when all cars are under the wire he/she makes changeover. Inbound to New York the engineer lowers the pantographs before running out of the overhead wire and when the shoes make contact with the third rail the train is all set to continue.
As for moving the changeover area from Woodlawn to east of Mount Vernon in my opinion it was a very smart move. If a train has a changeover problem it is already well clear of Woodlawn and does not tie up switches at either Woodlawn or Mount Vernon. Just as important are the low overhead bridges between Woodlawn and Mount Vernon which have been a problem with water plus salt leaking in the winter weather and water at all times. We used to have a lot of grounds in that area even when there were no trains in that area, this has done away with that problem.
Noel Weaver

Additionally, the new changeover point is on straight, level track, a luxury not available when there were two separate corporate entities. Coming down off the hill, onto the Harlem Division, was the easy part. Changing over while trying to blast uphill could be problematic, especially if something went wrong (which was not a problem when the equipment was new).

Most (all?) New Haven electric equipment included a protective relay that would fire to lower the pantograph if there was 600V on the third rail shoes.

it still does on all, including the M-8's, its requirement by FRA that no two sources of power are present or active at same time on the train.

Kilgore Trout wrote:Most (all?) New Haven electric equipment included a protective relay that would fire to lower the pantograph if there was 600V on the third rail shoes.

This feature was new when the M-2's came on the scene in 1972. No New Haven electric locomotive or MU had anything of this sort. We did not have the FRA in those days either although the ICC ran shotgun on some things the design of equipment was pretty much left to the railroads and the manufacturers and designers. There wasn't much that was automatic in those days, somehow we were able to get over the road with them though.
Noel Weaver

Even though the NYC and the NYNY&H were as Statkowski points out two separate entities, would anything have precluded the NH from extending the third rail east of Woodlawn to a level straightaway as it is now, and avoid the change-over on a grade as well as the water issues through Mount Vernon?

With regard to the post regarding the changeover location, up until the mid 1950’s the New Haven used AC electric motors for both through and local freight operations and in the case of Mount Vernon there were sidings at both South Mount Vernon and at Mount Vernon itself. Having no wires in that area would have forced the railroad to use steam on these jobs until the diesels came. The electrics were replaced by diesels in the mid 50’s and I suppose after that they could have extended the third rail to a point east of Columbus Avenue. There would have been a couple of problems still in that the New Haven did not produce nor control DC and they would have had to pay the New York Central to provide the power and control the power in this area. In so far as the grade was concerned at Woodlawn that was not really a problem as we seldom had power coasting eastbound through that area even with a long train of MU’s. As it was we had to pay the New York Central for the DC electricity that we consumed and this was figured by use of a watt meter on every AC/DC electric locomotive, MU motor car and FL-9. On electric motors and FL-9’s the fireman made out a meter slip with the meter readings and turned it in with the timeslip for every trip. In the case of MU motor cars the meters were read once a month. We also had to take AC watt meter readings on the trains to and from Penn Station east of Harold and again at Oak Point for the PRR and New York Connecting portions of the trip. Needless to say that I did not always actually take the readings, I could fudge the figures on the meter slip and nobody knew the difference.
The DC watt meters were maintained and sealed by the New York Central who had a meter inspector at Grand Central Terminal to maintain these things.
Noel Weaver

Noel,

Fascinating, just fascinating to hear about how it was done back then. A person dedicated to reading the meters of how much of a foreign road's juice was consumed in a given time period.
I bet that the statute of limitations has since passed regarding any reprimands for cuffing the wattage reports.

Thanks.

Noel -

Thanks again for your insight. Did both the NYC and Pennsylvania metering systems measure in kilowatt hours? Do you also remember roughly how much was the typical charge for a single locomotive for a round trip to GCT?

Noel Weaver wrote:On electric motors and FL-9’s the fireman made out a meter slip with the meter readings and turned it in with the timeslip for every trip. In the case of MU motor cars the meters were read once a month. -

The DC watt meters were maintained and sealed by the New York Central who had a meter inspector at Grand Central Terminal to maintain these things.
Noel Weaver

Yes it was KW hours but I do not have a clue as to what the New Haven paid either the New York Central or the PRR for electricity. The New York Connecting came into the picture as well but that was jointly owned by the New Haven and the PRR so I guess that was a bookkeeping situation only. They also paid the Long Island for electricity used between Fremont and Bay Ridge but in that situation my experience there was only on the Virginian Motors and the Virginians did not have wattmeters on them for us to read so I suppose it might have been a flat rate situation. The AC meters were maintained by the New Haven as the New York Central did not have any AC electricification.
Noel Weaver

Regarding that the New Haven was cash short all the time, were there orders on the electrics to try to "conserve" the use of DC power? Was that possible?

BobLI wrote:Regarding that the New Haven was cash short all the time, were there orders on the electrics to try to "conserve" the use of DC power? Was that possible?

NO
Noel Weaver