Welcome to the forum! Your English is perfectly clear, thanks for making the effort!Hi everybody and greetings from Italy!!
Please, forgive my "rusty" English.
I've been following the IET's deeds from the beginning and there's something that still escapes me.
According to Hitachi's own literature (1), inner frame bogies allow a weight saving of 2.5 tons per bogie (that's 5 tons per car...), they boast also a considerable smaller footprint, allowing the fitment of skirtings/fairings very useful (reduced noise and aerodynamic resistance) to a stock designed for speeds up to 140.
They could also give a non negligible contribution (minus 10 tons) to the "power-to-weight ratio-in-Diesel-mode" issue that's keeping so many people concerned...
Most of early sketches/rendering seemed to suggest they were going to be fitted in the front carriages of every IET but when the first 800's hit the rail, they weren't there....
Why?
I hope I made myself clear enough and accept my apologies if the question was answered before.
(1)
Hitachi Review Vol. 61 (2012), No. 7
Advanced Train Technology and New Development for
Global Markets
I was hoping someone more knowledgeable would reply, but my best guess as to why inner frame bogies were not used in the driving cars is that it proved cheaper and easier to maintain if all the bogies followed the same design. Fairings would impede maintenance, and the dynamic envelope (how far the train rocks when moving at speed) might have been different with different bogies. Maybe they would have gone to the extra expense to accommodate the issues if they had been missing targets on total weight, but otherwise it wasn't worth it.
If anyone actually knows (or can find out) the real answer to ETR401's question, please post!
