I dont think it depends on either my suggestion to Rail Board or some bloggers blogging in IRI,whether the WDP4 will be painted or not.If Correspnding Zones think it'll get painted easily.Discussion of such topics in blog doesnt yeild any benefit for the travellers.Anyways,some GZB WAP7's are there which have become black from Milky White due to Dirt wrap,still they're capable of doing 130 kmph.