Here are some trains, and their weights. The headline figure is weight per linear meter of length, but also includes other metrics of interest. Not included is any feature of interior design, such as the number of seats or the number and location of doors, as those reflect choices about seated vs. standing capacity and about the relative importance of quick boarding and alighting.
Most trains on the list are low-speed commuter trains, but a few are high-speed. All are EMUs, except for high-speed trains with dedicated power cars and two DMUs that are included for comparison. All are single-deck except the TGV Duplex, which is as light as a single-deck TGV.
All figures are in metric units. Length and width are in meters, weight in tons, and (short-term) power in megawatts. Load is the average weight in tons per axle; it is not the same as the axle load, which is the maximum loaded weight per axle. To the best of my ability, I’ve tried to give dry weights, without passengers, though I believe the N700 Shinkansen number is with passengers.
For English units, 1 metric ton per linear meter equals 0.336 short tons per linear foot.
|E231 Series motor||20||28.5||2.95||0.38||13.3||7.1||1.43|
|DBAG Class 423||67.4||105||3.02||2.35||22.4||10.5||1.56|
|A-Train, Japan (E257)||185.5||306||2.95||2.9||9.5||8.5||1.65|
|E751 Series motor||20.5||34||2.98||0.58||17||8.5||1.66|
|DBAG Class 425||67.5||114||2.84||2.35||20.6||11.4||1.69|
|BR Class 357||83||158||2.8||1.68||10.7||9.9||1.9|
|Coradia Cont., 4 cars||71||140||2.92||2.88||20.6||14||1.97|
|Francilien (SNCF Z 50000), 8 cars||112.5||235||3.06||2.62||11.1||13.1||2.09|
|A-Train, UK HSR (BR 395)||121||265||2.81||3.36||12.7||11||2.19|
|Colorado Railcar, 1-level||26||67||3.2?||0.96||14.3||16.8||2.59|
The table separates Japanese, European, and American trains, the latter two with hardly any overlap. I did not include too many French and British commuter trains, and those are fairly heavy by European standards, but even they are a bit lighter than the M-7, the lightest modern FRA-compliant train (British trains tend toward 2 t/m, French trains toward slightly more). I did include the lightest European trains I know of but not all the Japanese trains, selected mainly for the big Tokyo-area workhorses (E231, E233) and longer-range, higher-speed JR East trains that I thought were comparable to the needs of longer-distance American regional lines.
Eyeballing the non-American trains, I think it’s fair and unambitious to think of a train of the future that weighs 1.8 tons per meter, can achieve 15 kW/t, and is capable of 160 km/h. Multiple vendors beat that, often by a large enough margin to cushion against the slight weight increase coming from a wider loading gauge. The upshot of this is that any regulatory overhaul and regional rail revival in the US has to be coupled with a large train order replacing older, less capable trains over time, which means dropping an order for several thousand EMUs over 20 or so years. No single company can make all of these, but sharing in the order, as was done for the R160, could work.