The defending company said that in the year to March its profit would be "not less than pounds 11m" before tax, on the strength of recent strong trading and improving order books. The dividend forecast was also raised to 13p for the full year.
The bid from Triplex is at 309p against Friday's close of 370p, and the City is convinced that Triplex will have to decide later this week whether to bid again at well above 400p or withdraw.
William Cook's shares have been tightly held and not widely traded, with eight institutions owning 60 per cent and family members owning another 7.5 per cent.
William Cook has claimed that this illiquid market in the shares has depressed the market price. This has not reflected the full value of the company, whose rating is low compared with the rest of the sector.
Andrew Cook, chairman, said there were further new orders on the cards as rail companies bought new rolling stock to fulfil franchise commitments, and he urged investors to reject the Triplex bid.
The figures were dismissed as an "immaterial increase" by Triplex Lloyd, which said the latest forecast dividend was still below the level paid in 1991.