The industrial engineering category was at the bottom of the pile on Wednesday as the share prices of sector peers Weir Group, Avingtrans and Molins all dropped sharply on the back of disappointing results.Blue chip engineer Weir, which operates in the minerals, oil and power markets, plunged over 9% to 1,697p after warning of a "significant reduction" in constant-currency group revenues this year after 9% growth in 2014.The group blamed the gloomy outlook on the recent sharp decline in the price of oil and its associated impact on demand for its services. Strategic progress and cost initiatives will not be enough to completely offset this.Weir also announced that it would cut 22% of its North American workforce in its Oil & Gas division, or about 650 staff, to in-source production and reduce operating costs.IMI and Pressure Technologies, which both have exposure to the energy engineering markets, were also falling sharply in London.Similarly, Avingtrans, which makes components for oil and gas extraction and processing equipment amongst other things, also dropped nearly 10% after weaker oil prices led to 14% tumble in first-half revenues."The oil price storm brewed up quickly and unexpectedly, catching out large and small players in the market alike," said chairman Roger McDowell. He said that the oil sector forecast "can't get materially any worse for us".Meanwhile, FMCG machinery manufacturer Molins reversed 11% after reporting an underlying pre-tax profit of £3.3m in 2014, down 39% on the year before as its tobacco machinery division was hit by geopolitical conditions and general market weakness.Top performing sectors so far todayOil Equipment, Services & Distribution 18,013.01 +3.20%Forestry & Paper 14,412.08 +2.14%Food & Drug Retailers 3,318.86 +1.06%Technology Hardware & Equipment 1,339.43 +0.75%Mining 15,313.78 +0.46%Bottom performing sectors so far todayIndustrial Engineering 9,386.36 -3.48%Automobiles & Parts 8,580.70 -1.77%Beverages 14,899.26 -1.15%Mobile Telecommunications 5,075.97 -1.03%Chemicals 11,609.76 -0.92%