The longer tracks in England in those days would see 50-60mph maybe more on the straights. The rode on burnt coal ashes or cinders as they're called before they switched to crushed shale.
Mustn't think they were slow just because it was a long time ago.
This guy looks like he's really flyin...
That thing what looks like he has something big in his pocket....that's the leg hook..
This is called leg trailing style. It has come back into practice after a long time of leg leading style.
BTW the fellow in your avatar looks like one of the Speedway stars of this era....