GG-1 Question

[pajrr]

Hi! I have a question about the intake grills on a GG-1. Some have large, rectangular grids up high just below the pantographs. Others have long, narrow grills about half way up the side. I know that they were modified over the years. Which was the modified version, the high grills or the low grills? Thanks. pajrr

[Overmod]

High grilles.

Some of this was a response to a snowstorm in 1958 that featured very fine snow at just the wrong height.  This was sucked in through the low grilles and disabled a large proportion of the G's simultaneously.  The high grilles were an attempt (successful) to ensure a non-recurrence.  There are posts on the Web and on a couple of the PRR discussion lists that describe the problem in detail.

[NorthWest]

Interesting that the snow is still an issue with today's HSR, most notably (in my memory) the disabling of the Eurostars a couple years back...

 

In this picture: http://www.rrpicturearchives.net/showPicture.aspx?id=509821, it appears 4922 doesn't have upper grilles, but 4876 does. Are these the grilles we are discussing?

[pajrr]

Thanks for the information. I knew that the reason for the modification  was because of issues with snow. I just wasn't sure which way the modification was. The GG-1s I have seen in museums have the lower grilles. That is why I wasn't sure which was which.

[Overmod]

NorthWest

In this picture: http://www.rrpicturearchives.net/showPicture.aspx?id=509821, it appears 4922 doesn't have upper grilles, but 4876 does. Are these the grilles we are discussing?

Yes.  But there is an even more pronounced version of the high-mounted grilles.  Wes Barris covers this whole business better than I can, here.

[daveklepper]

There was also some experimentation with filters of various types, and this allowed the GG-1's that had not been converted to high grilles to retain their low grilles with a new and more effective filter type.

[CP GREEN]

Back in winter 1967 at Greenville Yard, Jersey City, NJ, I asked a trainman why there were SD35, SD40, GP30,35 and 40 models on the road freights rather than the GG1's and E44's and he responded that the blowing snow would be sucked in the vents and short out the traction motors. Didn't want the winter to be over that year as I was seeing diesels that were normally used west of Harrisburg. Man I loved it.

[Deggesty]

As I recall, the snow that caused the trouble was particularly fine, which made it possible for it to get where it was not wanted.

[ndbprr]

It is extremely rare for east coast snow to be anything but wet and heavy. Makes great snowballs and snowmen. The fact that the g's were not even slowed up for twenty years after introduction atests to the rarity of the problem.

[BaltACD]

I seem to recall several East coast snow storms that were heavy and wet enough to tear down the PRR catenary and put the GG-1's (and all the other classes of electric locomotives) out of service.

[ndbprr]

Having thought about this for a couple of days my hazy memory is telling me that the original filters were silk and it wasn't snow. It was ice crystals making an ice fog at the height of the filters. That is why it got through the filters causing short circuits.

[Rainhilltrial]

The Eurostar issue wasn't "snow" but a combination of factors. There was a public report issued which detailed exactly why two Eurostar trains (with passengers) lost power and got stranded inside the Chunnel under the English Channel. Another three Eurostar trains, delayed by the other two, also developed problems in the tunnel, and two trains had to be evacuated sitting in the Chunnel.

One issue was a lack of maintenance on seals which allowed snow to enter high-voltage areas. Another was accumulation of humidity in Eurostar power cars (technically locomotives) and water is never a good thing in proximity to electricity.

What compounded the problem is the environment inside the Chunnel tunnel (which is actually two separate rail tunnels with a third maintenance/emergency access 1-vehicle-wide access tunnel in between. The Eurostar power cars release a lot of heat during operation, and even though the 2 Chunnel bores are ventilated from both coasts, the warm air inside the tunnels will support a lot of humidity. The incident occurred during the winter. Cold air outside the tunnels. Hot humid air inside. The air and humidity mix (and the power car deficiencies) were "just right" to create the incident.

The entire independent review/report was published and is on the web. Do a search for "Eurostar independent review", interesting reading!