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Re: Bi-modal electric and diesel railcars not performing very well
Author: Max Wyss
Date: 11-30-2018 - 23:04
There is actually not much technical info available (or I am too stupid to find it) online about the Alstom Coradia Liner 160 trains. They are all low-floor articulated trains, available as straight electric, straight diesel or bi-mode. Originally designed for regional service, the Liner has better comfort, and is used for longer distance services (such as Paris-Mulhouse, or Lyon-Nantes).
The trains mentioned in the article have 269 seats in total on a length of 110 m. Power is 1300 kW in diesel mode and 2600 kW in electric mode. I did not find any weights, therefore, I can not say anything about the specific power. However, acceleration looks adequate, even in diesel mode (for longer distance service) with 0.5 m/s2.
The Paris-Mulhouse line is very easy, with maximum grades of 0.7%, which is probably also the reason why it did not get too much priority to electrification, although parts of it are.
So, what are the issues here?
Capacity.
The new trains replace loco-hauled sets (CC 72100, 2500 kW plus Corail cars) with capacity up to 450 seats (or so). Although the new trains could run MUed, there are not enough available (5 sets in total), so most (of the 3 daily services) are operated with a single unit. Note, there are more direct trains between Paris and Mulhouse, but they are TGVs, not using the line we talk about.
Comments to the article:
The "fuel tanks too small" argument sounds a bit weak to me, although if the train is packed with standees, it will need more power, and with the 1300 kW available it has to run at full load for keeping the 140 km/h allowed on most of the non-electrified sections. It could be an organizational issue, meaning that they may not "gas up" after every trip.
Breaking down often… well, the trains are about 2 years old now, and there are still bugs to be fixed. That should improve over the years.
Comments to the message:
Electrodiesels are a compromise, and the available power on diesel is very limited, which translates to lower maximum speeds and lamer acceleration. One sees that quite a bit on the Great Western line in the UK, where the new Class 800 trains run very nicely under wire, but get sluggish (some say even worse than the HST sets they replace) in diesel mode. What speaks in particular against EDMUs is a comfort issue; the diesel motors are smaller, agreed, but they are either underfloor on on the roof (as on the Coradia Liners), and even the best insulation can not sufficiently shield noise and vibrations (and, by comparing the specs, the SNCF has a bit tendency to underpower their trains).
I don't know enough about the line profile between San Jose and Wasco. If it is easy (grades less than 1%), diesel operation could be adequate. Tunnels can be an issue, however. Just FWIW, in Switzerland, regular diesel operation is banned through tunnels longer than 2 km (and I remember the days when they ran ICE-TD sets between Zürich and München, where the Zürich Airport station stank for quite a long time after when they stopped there).
With the new regulations, Alstom Coradia trains (note that "Coradia" is the name of a wide range of DMU/EDMU by Alstom) could be procured in the US. It is just the question whether they would be sufficiently powered. Conceptually, the diesel FLIRT looks more promising to me (considering the 1920 kW diesel power in the 4-car BMU for Greater Anglia); and if longer trains are preferred, 2 power packs could be installed in an 8-car BMU). Or, to make the trains more environmentally friendly, diesel/battery power packs could be used.
The trains mentioned in the article have 269 seats in total on a length of 110 m. Power is 1300 kW in diesel mode and 2600 kW in electric mode. I did not find any weights, therefore, I can not say anything about the specific power. However, acceleration looks adequate, even in diesel mode (for longer distance service) with 0.5 m/s2.
The Paris-Mulhouse line is very easy, with maximum grades of 0.7%, which is probably also the reason why it did not get too much priority to electrification, although parts of it are.
So, what are the issues here?
Capacity.
The new trains replace loco-hauled sets (CC 72100, 2500 kW plus Corail cars) with capacity up to 450 seats (or so). Although the new trains could run MUed, there are not enough available (5 sets in total), so most (of the 3 daily services) are operated with a single unit. Note, there are more direct trains between Paris and Mulhouse, but they are TGVs, not using the line we talk about.
Comments to the article:
The "fuel tanks too small" argument sounds a bit weak to me, although if the train is packed with standees, it will need more power, and with the 1300 kW available it has to run at full load for keeping the 140 km/h allowed on most of the non-electrified sections. It could be an organizational issue, meaning that they may not "gas up" after every trip.
Breaking down often… well, the trains are about 2 years old now, and there are still bugs to be fixed. That should improve over the years.
Comments to the message:
Electrodiesels are a compromise, and the available power on diesel is very limited, which translates to lower maximum speeds and lamer acceleration. One sees that quite a bit on the Great Western line in the UK, where the new Class 800 trains run very nicely under wire, but get sluggish (some say even worse than the HST sets they replace) in diesel mode. What speaks in particular against EDMUs is a comfort issue; the diesel motors are smaller, agreed, but they are either underfloor on on the roof (as on the Coradia Liners), and even the best insulation can not sufficiently shield noise and vibrations (and, by comparing the specs, the SNCF has a bit tendency to underpower their trains).
I don't know enough about the line profile between San Jose and Wasco. If it is easy (grades less than 1%), diesel operation could be adequate. Tunnels can be an issue, however. Just FWIW, in Switzerland, regular diesel operation is banned through tunnels longer than 2 km (and I remember the days when they ran ICE-TD sets between Zürich and München, where the Zürich Airport station stank for quite a long time after when they stopped there).
With the new regulations, Alstom Coradia trains (note that "Coradia" is the name of a wide range of DMU/EDMU by Alstom) could be procured in the US. It is just the question whether they would be sufficiently powered. Conceptually, the diesel FLIRT looks more promising to me (considering the 1920 kW diesel power in the 4-car BMU for Greater Anglia); and if longer trains are preferred, 2 power packs could be installed in an 8-car BMU). Or, to make the trains more environmentally friendly, diesel/battery power packs could be used.
