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Re: SP gear ratios
Author: Dr Zarkoff
Date: 12-20-2010 - 11:47
> I'm not aware of any place on the SP (well, in the
> diesel age, at least) where tha Maximum Authorized
> Speed for passenger trains was higher than 79
> M.P.H. WAF or JWL, do you know of any places
> where it was higher? That being the case, units
> with so-called "passenger gearing" regardless of
> manufacturer had their overspeed set at a nominal
> 83 MPH, while dual-service freight/passenger units
> with "freight gearing" had their overspeed set at
> 72. This would come into play with the SDP45s,
> which were delivered with 62:15 "freight gearing"
> and it quickly became obvious that they couldn't
> maintain the passenger schedules because of it, so
> they were re-geared. Likewise, when F-units with
> (62:15 or lower) "freight gearing" were used on
> passenger trains, they restricted to train to the
> lower speed for those units. (Actually, it was a
> piece of cake to cut out the overspeed on units
> with 24-RL brake equipment - been there, done that
> - but it wasn't a particularly good idea.)
>Nope. In the early days of the COSF (30s) along the Cal-P, it was 90 with ATC
ATC was on the line from Pittsburg to Shellmound (West Div TT #227, of 2/6/38). There is a large cast iron sewer running under the main lines at the west end of Tunnel 1 in SF, and if the ATS wasn't shut off on the leading unit before a pool 2 train left Oakland, when the engine passed over this sewer on the way to Mission Bay, it would frequently put the train in emergency.
The Cal-P technically is the line from Benicia to Sac, and it never had ATC. I've seen an SP speed chart (a long roll of paper) with the speeds listed in graphical form for the opening day of trains 9/10. From the curve just west of Bahia to Davis, it was 85 mph (except for 25 through Dixon, per city ordinance). The up the West Valley it was pretty much 85 the whole way. 9/10 never ran with steam engines, except for perhaps rare occasions. It also depends on what you mean by "the diesel era" -- after the 4460 made its last trip? If so, then there was no greater-than-79 trackage on the SP.
How fast a given train actually went and where it did it depended on the degree of oversight by the ICC/FRA and/or SP. For example, in 1974, when the speed limit across the Suisin marshes was 70, I was on #11 firing for a 1930s guy who went 85. I once ran a Rule 33 train at 60 mph down the Cal-P (SP AB Rule 33 specified that if the train is over 80 tons per operative brake, then it was limited to 45). "Once" is the operative word because when I did need to slow down, the train simply didn't want to. In the time period of these examples, the SP didn't use speed recorders, and neither the OS, alertor, nor deadman pedals were always sealed. If they were, enforcement of the seals wasn't all that rigorous. However, this was before the Ricky Gates (Gunpow) and Lamoken, DE, wrecks.
The ATC from Stanford to Gold Run lasted into the early 1960s. It's also can be a piece of cake to cut out the overspeed on 26-L (some cut-outs are in the nose, some are under the floor). On the SP 8400s and 8800s, along with a lot of the GPs, cutting out he foot pedal was simply a matter of flipping an unsealed toggle switch.
> diesel age, at least) where tha Maximum Authorized
> Speed for passenger trains was higher than 79
> M.P.H. WAF or JWL, do you know of any places
> where it was higher? That being the case, units
> with so-called "passenger gearing" regardless of
> manufacturer had their overspeed set at a nominal
> 83 MPH, while dual-service freight/passenger units
> with "freight gearing" had their overspeed set at
> 72. This would come into play with the SDP45s,
> which were delivered with 62:15 "freight gearing"
> and it quickly became obvious that they couldn't
> maintain the passenger schedules because of it, so
> they were re-geared. Likewise, when F-units with
> (62:15 or lower) "freight gearing" were used on
> passenger trains, they restricted to train to the
> lower speed for those units. (Actually, it was a
> piece of cake to cut out the overspeed on units
> with 24-RL brake equipment - been there, done that
> - but it wasn't a particularly good idea.)
>Nope. In the early days of the COSF (30s) along the Cal-P, it was 90 with ATC
ATC was on the line from Pittsburg to Shellmound (West Div TT #227, of 2/6/38). There is a large cast iron sewer running under the main lines at the west end of Tunnel 1 in SF, and if the ATS wasn't shut off on the leading unit before a pool 2 train left Oakland, when the engine passed over this sewer on the way to Mission Bay, it would frequently put the train in emergency.
The Cal-P technically is the line from Benicia to Sac, and it never had ATC. I've seen an SP speed chart (a long roll of paper) with the speeds listed in graphical form for the opening day of trains 9/10. From the curve just west of Bahia to Davis, it was 85 mph (except for 25 through Dixon, per city ordinance). The up the West Valley it was pretty much 85 the whole way. 9/10 never ran with steam engines, except for perhaps rare occasions. It also depends on what you mean by "the diesel era" -- after the 4460 made its last trip? If so, then there was no greater-than-79 trackage on the SP.
How fast a given train actually went and where it did it depended on the degree of oversight by the ICC/FRA and/or SP. For example, in 1974, when the speed limit across the Suisin marshes was 70, I was on #11 firing for a 1930s guy who went 85. I once ran a Rule 33 train at 60 mph down the Cal-P (SP AB Rule 33 specified that if the train is over 80 tons per operative brake, then it was limited to 45). "Once" is the operative word because when I did need to slow down, the train simply didn't want to. In the time period of these examples, the SP didn't use speed recorders, and neither the OS, alertor, nor deadman pedals were always sealed. If they were, enforcement of the seals wasn't all that rigorous. However, this was before the Ricky Gates (Gunpow) and Lamoken, DE, wrecks.
The ATC from Stanford to Gold Run lasted into the early 1960s. It's also can be a piece of cake to cut out the overspeed on 26-L (some cut-outs are in the nose, some are under the floor). On the SP 8400s and 8800s, along with a lot of the GPs, cutting out he foot pedal was simply a matter of flipping an unsealed toggle switch.
