Composite brake blocks in winter?

[bengt]

Here in Sweden we since about 2001 have to change out cast iron brake blocks for composite blocks due to some Central European countries dont like the noise from freight trains pasing by their cities.
But the composite shoes cause problems as bad braking characteristics due to ice and also for overheating wheels. In Europe the braking force for freight cars is higher or much higher in relation to carriage weight than in America. Up to 90 % of car weight.
Are there any problems in America with composite blocks compared to cast iron blocks in winter and severe winter conditions?

[Passenger]

Asbestos?

[DutchRailnut]

ehh no , its a plastic composite. yes composite blocks have problem with catching snow/ice and suck at slow speeds because of that.
on passenger trains they solve that problem with snow brake a feature that keeps a little pressure on , so block stays against wheel at little force.
problem with that is slack adjusters do not cycle. the composite blocks also polish the wheel more than cast iron shoes did .

http://frenoplast.eu/19683,2.dhtml" onclick="window.open(this.href);return false;

[Engineer Spike]

I run freight in the US and Canada. The composition shoes (blocks) don’t tend to be very good in snow. My personal technique is to use the brakes more. This is done where I would normally use dynamic brake, or just use the grade profile. This helps to keep the wheel treads somewhat clear. Even so, sometimes you don’t get the braking power which you expect. Other times you start to think that the brake has too much ice buildup, but as the brakes heat up, eventually it starts working. The key is to make the application early. If not, a heavy application will result in too much brake, once they finally heat up. I too notice that low speed braking is not very good.