The advantages of this arrangement are evident: since the springs have to receive only a part of the shocks, they can be made less strong and therefore more flexible. The danger of running off the track and that of breaking axles, springs and hangers, is therefore reduced by the use of equalizing levers. QUESTION 302. _How are the equalizing levers constructed?_ _Answer_. They are made of wrought iron and are supported in the centre by a fulcrum, _C_, which is fastened to the frame or boiler or both. The spring-hangers _g′, g′_ are usually attached to the lever by eyes and keys. Sometimes eyes are made in the lever, as shown in fig. 169, and the hanger is inserted into the eye and held either with a key or else with projections which are forged on the hanger below the lever. In other cases the hangers are made with an eye which embraces the end of the lever. QUESTION 303. _How is the distribution of weight of the engine affected by the equalizing levers?_ _Answer_. The weight is equally distributed on all the driving-wheels. This is apparent if it is observed that the weight suspended from each of the spring-hangers of each spring in fig. 169 must be the same; for if the weights in the two hangers, _g′_ and _g′_, were unequal, then the end of the spring which supports the heaviest weight would be drawn down until the pressure was equalized. If the weights suspended from the two hangers, _g′_ and _g′_, attached to the equalizing lever were unequal, then the one supporting the greatest load would draw up its end of the equalizer until the weights were again in equilibrium. [Illustration: _Fig. 184._ _Fig. 185._ Scale ³⁄₈ in. = 1 foot.]