movement speeds are now saved.

it's done kinda weird, but it's to be sure it doesn't conflict with the other movement stuff saved in the optional entity data that needs to be dealt with in 4.5.

this is good enough for now.

src/main/java/train/common/api/AbstractTrains.java

@@ -16,6 +16,7 @@
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTTagCompound;
+import net.minecraft.nbt.NBTTagList;
 import net.minecraft.util.AxisAlignedBB;
 import net.minecraft.util.ChatComponentText;
 import net.minecraft.util.DamageSource;
@@ -371,6 +372,7 @@ protected void writeEntityToNBT(NBTTagCompound nbttagcompound) {
         nbttagcompound.setBoolean("linked", this.linked);
         //nbttagcompound.setDouble("motionX", motionX);
         //nbttagcompound.setDouble("motionZ", motionZ);
+        nbttagcompound.setTag("Motion", this.newDoubleNBTList(this.motionX, this.motionY, this.motionZ));
         nbttagcompound.setDouble("Link1", Link1);
         nbttagcompound.setDouble("Link2", Link2);
 
@@ -409,6 +411,9 @@ protected void readEntityFromNBT(NBTTagCompound nbttagcompound) {
 		linked = nbttagcompound.getBoolean("linked");
 		//motionX = nbttagcompound.getDouble("motionX");
 		//motionZ = nbttagcompound.getDouble("motionZ");
+        NBTTagList nbttaglist1 = nbttagcompound.getTagList("Motion", 6);            this.motionX = nbttaglist1.func_150309_d(0);
+        this.motionX = nbttaglist1.func_150309_d(0);
+        this.motionZ = nbttaglist1.func_150309_d(2);
 		Link1 = nbttagcompound.getDouble("Link1");
 		Link2 = nbttagcompound.getDouble("Link2");
 		if(nbttagcompound.hasKey("Dim")){