Class 158 train on Southport line

[Llama]

70 tonnes is way wide of the mark, the underframes probably did need strengthening but not so much that it would more than double the weight of the DTS cars. A 319 unit weighs in at ~140t (~30/50/30/30t per vehicle). Unless Brush thought it would be a good wheeze to equip the 769s with redundant prime movers from HST power cars I think we can discount that.

 

[sprinterguy]

The extra 70 tonnes comes from reinforcing the end coaches to carry the weight of the engines and all the other associated extra equipment. The end coaches were never designed to carry that much weight, and on the tests the coaches proved that they couldn't carry it without the underframe flexing.

You're suggesting that the weight of the driving cars has been increased from 30 to 65 tonnes apiece? I don't think so.

The article I linked states that 7.5 tonnes is the total weight increase after all modifications have been made, there's nothing in addition to that:

The modifications add approximately 7.5 tonnes to the DT vehicle. In discussion about the impact of this extra mass, Simon revealed that finite element analysis of the bodyshell had been carried out, that the axles are strong enough, and that the suspension and brake cylinder pressures had been adjusted to compensate for the additional mass.

 

[Grannyjoans]

That's not as bad as I thought then. After further reading into this I heard that when running on diesel the power going to the traction motors will be about half that when running on electric. These are going to be pretty slow when running on diesel.

Will 769 flex be ready for March ? I'm sure it is already a year and a half late, as it was originally meant to enter service in the May 2018 timetable change.