Tasrail ZR2 adhesion

[jdennis@acslink.net.au (John Dennis)]

I was reading the latest issue of Tasmanian Rail News, and came across
an interesting description of the newly rebuilt ZR2.  One paragraph in
particular seemed unusual, to say the least:

"Initially the adhesion of the loco wheels to the rails is to be
assisted by the action of friction blocks onto the treads of each
wheel to control wheelslip, rather than by using sand."

Now I am familiar (at least in layman's terms) with the various modern
electronic techniques to improve adhesion, and also with the age old
method of sanding the rail, but applying friction to the wheel treads
does seem to me to be a little strange.

Can anybody out there shed some light on this.  Does it really work?

Cheers...JD
==========================================================
John Dennis                         jdennis@acslink.net.au
Melbourne                                  denjo02@cai.com
Australia               http://www.acslink.net.au/~jdennis
                  Dutton Bay Tramway pages updated 14 June