You might add that :
- They were all compatible together, any of them could be MUed with any other;
- Braking systems varied a lot, so there were sometimes strong reactions between units in a varied consist;
- Up to 660, they were equipped with classical rheostat system for starting, as of 660 they switched to thyristors;
- Motor couplings were serial and serial/parallel on the rheostat ones, and serial/parallel only for the thyristor ones; the controller only had those two stable positions - on the thyristor ones, to maintain compatibility, the serial position was simulated;
- Max speed was 130 km/h for units below 600 and 140 km/h for 601 and above
- Maximum consist was 6 units, but this draws too much current so one of the six had to have its traction switched off, unless they were all thyristor units, because they draw less current;
- Only those which are not thyristor-equipped are cleared to run into Aachen;
- the current cab design started with unit 010 (AM50, built 1950).
Yes I remember random combinations of all ages in mixed steel/green/red liveries. Also ran with AM75, which they still do of course.
Combinations of thyristor and non thyristor units are brutal. The older units take off more quickly so there is a big bang from the couplings. On the older units you can hear the camshaft control knocking out the resistors one by one. I think there are about 20 stages. If power is reapplied when the train is moving it's quite fun listening to the system working out which point to start from.
Why did 151 to 270 have a lower max speed? They had the same motors and disc brakes as 601 to 782, unlike units up to 150 which had tread brakes. I did once have a run on an AM62 coupled to the back of a newer unit. It ran quite happily at 140 km/h. If the AM62 is leading then a red light comes on in the cab at 130 km/h.
12 cars sets sometimes used to run on peak trains on line 50, Aalst-Jette-Brussel-Denderleeuw-Zottegem. One summer about 20 years ago they ran a summer relief train from Knokke and Blankenberge to Brussel. Six cars from each joining at Brugge. I travelled from Gent Sint Pieters for the high speed run along line 50A to Brussel Zuid.
I wonder why thyristor units cannot run to Aachen? Why are they planning to replace the old units with on that service?


