- Joined
- Jul 16, 2010
- Messages
- 4,888
On the northbound Carolinian today, I measured 113 between Baltimore and Wilmington using Speedometer app on my smartphone. Is this the fastest it goes? anyone measure better numbers?
I would expect that GPS tracking applications would use Kalman Filters or equivalent to smooth out the position and velocity errors. So the computation of the velocity is more complex than your example. Your point is valid, though, in that speed reported by GPS apps or GPS navigation devices should not be taken as always completely accurate. The speed reports have an error range and will jump around, despite using predictive Kalman filters. For example, if the app shows a short lived jump from a 124 mph reading on a Regional to 128 mph and then steadies back down to 123 to 124Most likely your GPS was slightly off. Accuracy for phone GPSs in urban areas and without clear view of the sky can be as much as 9-16 feet. ...
How much of the padding for the LD trains is to allow the faster Regionals. Keystones, and Acelas to maneuver around them? To provide time buffers to keep the LD train (or Carolinian) parked in a station or shunted off to the slow track so the 125 mph regionals and Keystones get pass them? If there is LD NEC schedule padding to allow for that, the padding could be trimmed, although it will have to wait until all the Viewliner IIs are delivered and the Viewliner Is are upgraded. Having a uniform fleet of more powerful ACS-64s in place of 3 locomotive types with less traction power may also allow for schedule trimming once all the AEM-7s and HHP-8s are retired. But this is probably at least 3 years away.I seriously doubt that the NEC schedules for the LD trains would be significantly adjusted. A significant part of the schedule now is padding to allow for the low priority they get on the NEC.
234 mph? Yikes, we just got a new bullet train with the Regional! (Or a really off GPS.)For example, if the app shows a short lived jump from a 124 mph reading on a Regional to 128 mph and then steadies back down to 123 to 234 mph. Does not mean that the train suddenly speed up by 4 mph and then slowed down 10 seconds later.Most likely your GPS was slightly off. Accuracy for phone GPSs in urban areas and without clear view of the sky can be as much as 9-16 feet. ...
oops. :unsure: Thanks for pointing out the typo.234 mph? Yikes, we just got a new bullet train with the Regional! (Or a really off GPS.)
You are correct.....the NEC runs along a stretch of the John Hanson Highway - US 50, from around Cheverly to around New Carrollton. Sorry my memory was fuzzy on that.US 50.
The NEC doesn't run along the B-W Parkway.
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