Speed limits on shared track

[Crowbar_k]

I read somewhere that the FRA does not allow speeds greater than 90 mph on tracks that are shared with passengers and freight. I know for a fact that this is not true, as the Michigan line runs at 110 mph, and so does a short section of Union Pacific track in Illinois. These sections of tracks are shared with passenger and freight. So, what is the real upper speed limit allowed for shared trackage?

 

[TinCan782]

A lot of other track is rated for 90 mph passenger and is shared with freight. The route of the Southwest Chief through eastern California, Arizona, etc is a good example of 90 mph passenger. Also part of the Pacific Surfliner route through Orange county which is maintained by the Southern California Regional Rail Authority and North County Transit District which also handles some freight. The freight speed is usually something less than passenger.
Track speed is determined by signaling and how the track is constructed and maintained (track class). There will be separate speeds for passenger and freight.
Track classes are listed in this article.
https://en.wikipedia.org/wiki/Rail_speed_limits_in_the_United_States

 

[GDRRiley]

125mph is the max you can run without wavers in mixed traffic. 160mph is the waver the NEC has to allow freight and multiple speeds of pax service to co exist.

 

[Crowbar_k]

A lot of other track is rated for 90 mph passenger and is shared with freight. The route of the Southwest Chief through eastern California, Arizona, etc is a good example of 90 mph passenger. Also part of the Pacific Surfliner route through Orange county which is maintained by the Southern California Regional Rail Authority and North County Transit District which also handles some freight. The freight speed is usually something less than passenger.
Track speed is determined by signaling and how the track is constructed and maintained (track class). There will be separate speeds for passenger and freight.
Track classes are listed in this article.
https://en.wikipedia.org/wiki/Rail_speed_limits_in_the_United_States

I know that, but I was once told that passenger trains cannot go faster than 90 mph on tracks shared with freight, but I know this isn't true.

 

[George Harris]

The real answer can be found in the FRA regulations, but I do not know the "chapter and verse". 90 and 100 mph passenger trains have been operated on shared track for many years. Usually freight speeds are 70 mph or less for several reasons. First, that is the gearing for most motors. Likewise, the wheelsets and suspensions on most freight equipment is regarded as good for no more than 70 mph. Second, higher speeds are relatively pointless in so far as time saving is concerned. Third, aerodynamic resistance is proportional to the square of train speed and freight trains are anything but smooth aerodynamically, so high freight speeds come at a significant penalty in fuel consumption.

 

[jis]

The exact regulatory gymnastics used may vary, but essentially, freight is allowed on all of NEC where passenger speeds currently may be as high as 150mph. However, due to extremely high trackage charger actual freight operation other than yard jobs may be restricted to certain segments. Still, I suspect P&W does operate on 150mph trackage up north in the New London - Providence area. NS operates regular freights between Perryville and Bayview Yard over currently 125mph track. There are Conrail Shared Asset locals that operate all over the NEC in NJ between Lane and Trenton.

 

[AmtrakBlue]

Through Newark, DE, on the NEC, the tracks that NS use are only 60 mph and I think 30 mph.